go.mod: update go directive to 1.18

There's no reason for this module to still be assuming the semantics
of Go 1.12. Pick 1.18 as a semi-arbitrary newer version because it's
used by a few other golang.org/x modules, and it's enough to get the
nice new features like module graph pruning, removed // +build lines,
and so on. See https://go.dev/ref/mod#go-mod-file-go.

Done with:

go get go@1.18
go mod tidy
go fix ./...

Using go1.21.1.

Change-Id: Icb6874f531accb433bf7e45e7ef0f65af118bf19
Reviewed-on: https://go-review.googlesource.com/c/image/+/526895
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Nigel Tao <nigeltao@golang.org>
Commit-Queue: Nigel Tao <nigeltao@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Nigel Tao (INACTIVE; USE @golang.org INSTEAD) <nigeltao@google.com>
diff --git a/ccitt/gen.go b/ccitt/gen.go
index bf8aa7f..0f849f2 100644
--- a/ccitt/gen.go
+++ b/ccitt/gen.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 package main
 
diff --git a/colornames/gen.go b/colornames/gen.go
index f0c2ea0..e799e5c 100644
--- a/colornames/gen.go
+++ b/colornames/gen.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 // This program generates table.go from
 // https://www.w3.org/TR/SVG11/types.html#ColorKeywords
diff --git a/draw/draw_go117.go b/draw/draw_go117.go
index fa83648..2e97caa 100644
--- a/draw/draw_go117.go
+++ b/draw/draw_go117.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build go1.17
-// +build go1.17
 
 package draw
 
diff --git a/draw/gen.go b/draw/gen.go
index 1646932..c112a1b 100644
--- a/draw/gen.go
+++ b/draw/gen.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 package main
 
diff --git a/font/basicfont/gen.go b/font/basicfont/gen.go
index fa25e60..44f012c 100644
--- a/font/basicfont/gen.go
+++ b/font/basicfont/gen.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 // This program generates data.go.
 package main
diff --git a/font/sfnt/gen.go b/font/sfnt/gen.go
index 1708ce9..44b0044 100644
--- a/font/sfnt/gen.go
+++ b/font/sfnt/gen.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 package main
 
diff --git a/go.mod b/go.mod
index 182d1df..69ef328 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,5 @@
 module golang.org/x/image
 
-go 1.12
+go 1.18
 
 require golang.org/x/text v0.13.0
diff --git a/go.sum b/go.sum
index 3c46b32..82ce224 100644
--- a/go.sum
+++ b/go.sum
@@ -1,32 +1,2 @@
-github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
-golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
-golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
-golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
-golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
 golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
-golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
diff --git a/tiff/fuzz.go b/tiff/fuzz.go
index b27c540..b388b6f 100644
--- a/tiff/fuzz.go
+++ b/tiff/fuzz.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gofuzz
-// +build gofuzz
 
 package tiff
 
diff --git a/vector/acc_amd64.go b/vector/acc_amd64.go
index a6fa0ca..5b148c5 100644
--- a/vector/acc_amd64.go
+++ b/vector/acc_amd64.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !appengine && gc && !noasm
-// +build !appengine,gc,!noasm
 
 package vector
 
diff --git a/vector/acc_other.go b/vector/acc_other.go
index 3902269..e383d52 100644
--- a/vector/acc_other.go
+++ b/vector/acc_other.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !amd64 || appengine || !gc || noasm
-// +build !amd64 appengine !gc noasm
 
 package vector
 
diff --git a/vector/gen.go b/vector/gen.go
index 010608a..d820124 100644
--- a/vector/gen.go
+++ b/vector/gen.go
@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 package main