cmd/{admingolangorg,googlegolangorg}: update App Engine runtime to Go 1.19

Keep them up with the times.

Also rewrite googlegolangorg's .gcloudignore to more effectively include
only the bare minimum files using the same approach as in CL 406374.

Change-Id: Ibc42b164e0cfb8052af0ec560044a20c62fc8368
Reviewed-on: https://go-review.googlesource.com/c/website/+/456775
Reviewed-by: Jamal Carvalho <jamal@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/cmd/admingolangorg/app.yaml b/cmd/admingolangorg/app.yaml
index 732c020..1dd5e3e 100644
--- a/cmd/admingolangorg/app.yaml
+++ b/cmd/admingolangorg/app.yaml
@@ -1,5 +1,5 @@
-runtime: go116
 service: admin
+runtime: go119
 main: ./cmd/admingolangorg
 
 env_variables:
diff --git a/cmd/googlegolangorg/.gcloudignore b/cmd/googlegolangorg/.gcloudignore
index 199e6d9..2aa30a0 100644
--- a/cmd/googlegolangorg/.gcloudignore
+++ b/cmd/googlegolangorg/.gcloudignore
@@ -1,25 +1,11 @@
-# This file specifies files that are *not* uploaded to Google Cloud Platform
-# using gcloud. It follows the same syntax as .gitignore, with the addition of
-# "#!include" directives (which insert the entries of the given .gitignore-style
-# file at that point).
-#
-# For more information, run:
-#   $ gcloud topic gcloudignore
-#
-.gcloudignore
-# If you would like to upload your .git directory, .gitignore file or files
-# from your .gitignore file, remove the corresponding line
-# below:
-.git
-.gitignore
+# The googlegolangorg program needs a fairly short list of things
+# from the golang.org/x/website repository that probably doesn't
+# change often. Filter everything else out implicitly as long as
+# this approach needs less maintenance.
+**
+!go.mod
+!go.sum
+!cmd/
+!cmd/googlegolangorg/**
 
-# Binaries for programs and plugins
-*.exe
-*.exe~
-*.dll
-*.so
-*.dylib
-# Test binary, build with `go test -c`
-*.test
-# Output of the go coverage tool, specifically when used with LiteIDE
-*.out
\ No newline at end of file
+.gcloudignore
diff --git a/cmd/googlegolangorg/app.yaml b/cmd/googlegolangorg/app.yaml
index 6a5ffad..2ccb009 100644
--- a/cmd/googlegolangorg/app.yaml
+++ b/cmd/googlegolangorg/app.yaml
@@ -1,2 +1,3 @@
 service: google
-runtime: go112
+runtime: go119
+main: ./cmd/googlegolangorg