workflows: add auto-locking of inactive closed issues

Encourage people to file new issues so that we can track and
communicate more effectively on their current issues.

.github/workflows/lock.yml

@@ -0,0 +1,28 @@
+name: 'Lock Threads'
+
+on:
+  schedule:
+    - cron: '0 * * * *'
+  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: '30'
+          issue-comment: >
+            I'm going to lock this issue because it has been closed for _30 days_ ⏳.
+            This helps our maintainers find and focus on the active issues.
+            If you have found a problem that seems similar to this, please open a new
+            issue and complete the issue template so we can capture all the details
+            necessary to investigate further.
+          process-only: 'issues'