chore: change the way we look for upstream remote (#7230)

* chore: change the way we look for upstream remote

* chore: use js instead of shell

thanks christopher

Co-authored-by: Christopher Allen <cpcallen+github@gmail.com>

* chore: store the found upstream name

---------

Co-authored-by: Christopher Allen <cpcallen+github@gmail.com>

Author: maribethb

scripts/gulpfiles/git_tasks.js

@@ -36,9 +36,8 @@ let upstream = null;
 function getUpstream() {
   if (upstream) return upstream;
   for (const line of String(execSync('git remote -v')).split('\n')) {
-    const [remote, url] = line.split('\t');
-    if (url.includes('github.com/google/blockly')) {
-      upstream = remote;
+    if (line.includes('google/blockly')) {
+      upstream = line.split('\t')[0];
       return upstream;
     }
   }