Make the setup for the github mirroring workflow a little more robust

.github/workflows/mirror-pull-requests.yaml

@@ -25,9 +25,11 @@ jobs:
 
       - name: Fetch upstream refs
         run: |
-          git fetch origin '+refs/heads/*:refs/heads/*'
+          git fetch origin '+refs/heads/*:refs/remotes/origin/*'
+          git fetch origin '+refs/heads/master:refs/heads/master' || git pull
           git fetch origin '+refs/tags/*:refs/tags/*'
           git fetch origin '+refs/pull/*:refs/pull/*'
+          git fetch origin '+refs/devtools/*:refs/devtools/*'
 
       - name: Pull existing reviews
         run: go run github.com/google/git-appraise/git-appraise pull