Set version in release package.json

Before this was handled by an extra CI step, now we can just do it in
the release script.

Pulling it from the product.json since we already set it there, rather
than ask for it again via env var.

ci/build/build-release.sh

@@ -75,6 +75,7 @@ bundle_code_server() {
   jq --slurp '(.[0] | del(.scripts,.jest,.devDependencies)) * .[1]' package.json <(
     cat << EOF
   {
+    "version": "$(jq -r .codeServerVersion "./lib/vscode-reh-web-$VSCODE_TARGET/product.json")",
     "commit": "$(git rev-parse HEAD)",
     "scripts": {
       "postinstall": "sh ./postinstall.sh"