add lock actions

This is the new way of using lock bot. App was migrate to a Github actions. 
Running each hour at first - changing later

.github/workflows/lock.yml

@@ -0,0 +1,31 @@
+# From https://github.com/marketplace/actions/lock-threads
+name: 'Lock threads'
+
+on:
+  schedule:
+    - cron: '0 * * * *'
+
+jobs:
+  lock:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: dessant/lock-threads@v2.0.1
+        with:
+          github-token: ${{ github.token }}
+          issue-lock-inactive-days: '180'
+          # issue-exclude-created-before: ''
+          # issue-exclude-labels: ''
+          # issue-lock-labels: ''
+          issue-lock-comment: >
+            This old thread has been automatically locked. If you think you have 
+            found something related to this, please open a new issue by following 
+            the issue guide (<https://yihui.org/issue/>), and link to this 
+            old issue if necessary.
+          issue-lock-reason: 'resolved'
+          pr-lock-inactive-days: '180'
+          # pr-exclude-created-before: ''
+          # pr-exclude-labels: ''
+          # pr-lock-labels: ''
+          # pr-lock-comment: ''
+          # pr-lock-reason: ''
+          # process-only: ''