Lock closed issues/PRs via 3rd-party action (#772)

Lock closed issues/PRs via 3rd-party action

Author: chadwhitacre

.github/workflows/lock.yml

@@ -0,0 +1,15 @@
+name: 'Lock closed issues and pull requests'
+on:
+  schedule:
+    - cron: '*/5 * * * *'
+jobs:
+  lock:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: dessant/lock-threads@v2
+        with:
+          github-token: ${{ github.token }}
+          issue-lock-inactive-days: 15
+          issue-lock-reason: ''
+          pr-lock-inactive-days: 15
+          pr-lock-reason: ''