automate locking closed threads (#24525)

With comments happening on closed issues/prs this locks issues that have
been closed for >45days. This allows for comments on recently closed
issues/prs to still happen.

---------

Co-authored-by: silverwind <me@silverwind.io>

.github/workflows/lock.yml

@@ -0,0 +1,21 @@
+name: 'Lock Threads'
+
+on:
+  schedule:
+    - cron: '0 0 * * *' # Run once a day
+  workflow_dispatch:
+
+permissions:
+  issues: write
+  pull-requests: write
+
+concurrency:
+  group: lock
+
+jobs:
+  action:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: dessant/lock-threads@v4
+        with:
+          issue-inactive-days: 45