Apply actions/stale to pull request

Author: backpaper0

.github/workflows/close-inactive-issues.yml

@@ -14,7 +14,9 @@ jobs:
           stale-issue-label: "stale"
           stale-issue-message: "This issue is stale because it has been open for 60 days with no activity."
           close-issue-message: "This issue was closed because it has been inactive for 30 days since being marked as stale."
-          days-before-pr-stale: -1
-          days-before-pr-close: -1
+          days-before-pr-stale: 60
+          days-before-pr-close: 30
+          stale-pr-message: "This pull request is stale because it has been open for 60 days with no activity."
+          close-pr-message: "This pull request was closed because it has been inactive for 30 days since being marked as stale."
           repo-token: ${{ secrets.GITHUB_TOKEN }}