README.md: generate the version for nightly during release

And change back to the version from upstream.
That will ease the sync process and less confusing during migration.

Change-Id: I6b3a7e2157bdc586f9f5052ec1db46a86bbaed01
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/232459
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
diff --git a/build/all.bash b/build/all.bash
index 6dd46bf..7167864 100755
--- a/build/all.bash
+++ b/build/all.bash
@@ -73,8 +73,9 @@
 ') > /tmp/package.json && mv /tmp/package.json package.json
 
   # Replace CHANGELOG.md with CHANGELOG.md.nightly + Release commit info.
-  # TODO(hyangah): Update README.md
   printf "**Release ${VER} @ ${COMMIT}** \n\n" | cat - CHANGELOG.md.nightly > /tmp/CHANGELOG.md.new && mv /tmp/CHANGELOG.md.new CHANGELOG.md
+  # Replace the heading of README.md with the heading for Go Nightly.
+  sed '/^# Go for Visual Studio Code$/d' README.md | cat README.md.nightly - > /tmp/README.md.new && mv /tmp/README.md.new README.md
 }
 
 main() {