ci: only run Stale Action on specifically labeled issues and PRs (#549)

- only run on issues labeled with "problem/more information needed"
  - same as done in Workflows

- most issues and PRs are marked and closed as stale in this repo only because they've never been followed up on, not because they're missing information
  - for instance, a PR that never got a review or an issue with no maintainer response
  - we should only start the stale process for issues/PRs that need action from the contributor, not ones that need action from maintainers

Signed-off-by: Anton Gilgur <[email protected]>

.github/workflows/stale.yml

@@ -21,7 +21,13 @@ jobs:
     - uses: actions/stale@v9
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
+        # timing
+        days-before-stale: 14 # 2 weeks of inactivity
+        days-before-close: 14 # 2 more weeks of inactivity
+        # labels to watch for, add, and remove
+        only-labels: 'problem/more information needed' # only mark issues/PRs as stale if they have this label
+        labels-to-remove-when-unstale: 'problem/more information needed' # remove label when unstale -- should be manually added back if information is insufficient
         stale-issue-message: 'Stale issue message'
         stale-pr-message: 'Stale pull request message'
-        stale-issue-label: 'no-issue-activity'
-        stale-pr-label: 'no-pr-activity'
+        stale-issue-label: 'problem/stale'
+        stale-pr-label: 'problem/stale'