Update stale issues workflow to cover PRs correctly

Signed-off-by: Michael Herger <michael@herger.net>

Author: michaelherger

.github/workflows/close-stale-issues.yaml

@@ -9,8 +9,9 @@ jobs:
     runs-on: ubuntu-latest
     permissions:
       issues: write
+      pull-requests: write
     steps:
-      - uses: actions/stale@v9
+      - uses: actions/stale@v10
         with:
           days-before-issue-stale: 720
           days-before-issue-close: 14
@@ -19,4 +20,7 @@ jobs:
           close-issue-message: ":no_entry: This issue was closed because it has been inactive for 14 days since being marked as stale."
           days-before-pr-stale: 720
           days-before-pr-close: 14
+          stale-pr-label: "stale"
+          stale-pr-message: ":warning: This pull request is stale because it has been open for 720 days with no activity. Please chime in if you want to keep it alive."
+          close-pr-message: ":no_entry: This pull request was closed because it has been inactive for 14 days since being marked as stale."
           repo-token: ${{ secrets.GITHUB_TOKEN }}