Have create_release.py push the new branch automatically (#1255)

Having used this script for a while now I'm not sure there is any
point if leaving this last step as a manual push.

scripts/create_release.py

@@ -58,14 +58,15 @@ def main(args):
   branch_name = 'version_' + new_version
 
   # Create a new git branch
-  subprocess.check_call(['git', 'checkout', '-b', branch_name], cwd=root_dir)
+  subprocess.check_call(['git', 'checkout', '-b', branch_name, 'origin/main'], cwd=root_dir)
 
   # Create auto-generated changes to the new git branch
   subprocess.check_call(['git', 'add', '-u', '.'], cwd=root_dir)
   subprocess.check_call(['git', 'commit', '-m', new_version], cwd=root_dir)
+  print('New release created in branch: `%s`' % branch_name)
 
-  print('New relase created in branch: `%s`' % branch_name)
-
+  # Push new branch to origin
+  subprocess.check_call(['git', 'push', 'origin', branch_name], cwd=root_dir)
   return 0