workflows: git push with backoff

ported from linuxbrew-core

.github/workflows/publish-commit-bottles.yml

@@ -80,13 +80,14 @@ jobs:
           brew pr-pull --verbose ${{github.event.client_payload.pull_request}}
       - name: Push bottle commit
         run: |
-          for try in $(seq 10); do
+          for try in $(seq 20); do
             git fetch
             git rebase origin/master
             if git push; then
               exit 0
             else
-              sleep $(shuf -i 3-10 -n 1)
+              max=$(( $try + 10 ))
+              sleep $(shuf -i 3-$max -n 1)
             fi
           done
           exit 1