all: add a go.mod file

This change adds a go.mod and go.sum file to this repo, following the
requirements stated in bcmills's comment here:
https://golang.org/issue/28136#issuecomment-462971974. It's
important to note that we will not be
adding versions to the repo for now.

The change was generated by running "go mod init" and "go mod tidy" using Go
1.11.5 in the top-level directory of the repository.

Updates golang/go#28136

Change-Id: I837a30c514e23ddab0404a2d8ab66eaa6ad82961
Reviewed-on: https://go-review.googlesource.com/c/162912
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..bb8d03f
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module golang.org/x/image
+
+require golang.org/x/text v0.3.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..6bad37b
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=