actions: Add stale action to nrfxlib

This will ensure we reduce the list of old abandoned PRs.

Signed-off-by: Rubin Gerritsen <[email protected]>

Author: rugeGerritsen

.github/workflows/stale.yml

@@ -0,0 +1,18 @@
+name: "Close stale pull requests/issues"
+on:
+  schedule:
+  - cron: "16 00 * * *"
+
+jobs:
+  stale:
+    runs-on: ubuntu-24.04
+    steps:
+    - uses: actions/stale@v9
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-pr-message: 'This pull request has been marked as stale because it has been open (more than) 30 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this pull request will automatically be closed in 7 days. Note, that you can always re-open a closed pull request at any time.'
+        stale-issue-message: 'This issue has been marked as stale because it has been open (more than) 30 days with no activity. Remove the stale label or add a comment saying that you would like to have the label removed otherwise this issue will automatically be closed in 7 days. Note, that you can always re-open a closed issue at any time.'
+        days-before-stale: 30
+        days-before-close: 7
+        stale-issue-label: 'Stale'
+        stale-pr-label: 'Stale'