add post-release to PR titles

.github/workflows/leaderboard.yml

@@ -34,14 +34,14 @@ jobs:
         uses: peter-evans/create-pull-request@9153d834b60caba6d51c9b9510b087acf9f33f83
         with:
           token: ${{ secrets.MINIKUBE_BOT_PAT }}
-          commit-message: Update leaderboard
+          commit-message: 'Add leaderboard for ${{ github.ref_name }}'
           committer: minikube-bot <[email protected]>
           author: minikube-bot <[email protected]>
           branch: leaderboard
           push-to-fork: minikube-bot/minikube
           base: master
           delete-branch: true
-          title: 'Update leaderboard'
+          title: 'Post-release: Add leaderboard for ${{ github.ref_name }}'
           body: |
             Committing changes resulting from `make update-leaderboard`.
             This PR is auto-generated by the [update-leaderboard](https://github.com/kubernetes/minikube/blob/master/.github/workflows/leaderboard.yml) CI workflow.

.github/workflows/time-to-k8s.yml

@@ -36,5 +36,5 @@ jobs:
           push-to-fork: minikube-bot/minikube
           base: master
           delete-branch: true
-          title: Add time-to-k8s benchmark for ${{ steps.timeToK8sBenchmark.outputs.version }}
+          title: Post-release: Add time-to-k8s benchmark for ${{ steps.timeToK8sBenchmark.outputs.version }}
           body: Updating time-to-k8s benchmark as part of the release process