maintner/maintnerd/maintapi: stop testing x/website on Go 1.16

Testing x/website on Go 1.16.15 was helpful only until App Engine
started supporting¹ a currently-supported Go version like Go 1.19.

This undoes the change added in CL 393858, to be submitted around
the same time as x/website/cmd/golangorg/app.yaml's runtime value
goes from go116 to go119 or so.

¹ https://cloud.google.com/appengine/docs/standard/go/release-notes#December_07_2022

For golang/go#51800.

Change-Id: I621833060a160abf1fccdeb5b331582651eabc14
Reviewed-on: https://go-review.googlesource.com/c/build/+/456715
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>

maintner/maintnerd/maintapi/api.go

@@ -210,14 +210,6 @@ func tryWorkItem(
 				w.GoBranch = append(w.GoBranch, r.BranchName)
 				w.GoVersion = append(w.GoVersion, &apipb.MajorMinor{Major: r.Major, Minor: r.Minor})
 			}
-
-			// Test x/website with Go 1.16.15 in addition to the supportedReleases above.
-			// TODO(go.dev/issue/51800): Remove this once x/website deployment is updated.
-			if w.Project == "website" {
-				w.GoCommit = append(w.GoCommit, "7de0c90a1771146bcba5663fb257c52acffe6161") // go1.16.15 tag.
-				w.GoBranch = append(w.GoBranch, "release-branch.go1.16")
-				w.GoVersion = append(w.GoVersion, &apipb.MajorMinor{Major: 1, Minor: 16})
-			}
 		} else {
 			// A branch that is neither internal-branch.goX.Y-suffix nor "master":
 			// maybe some custom branch like "dev.go2go".