add workflow for handling answerable discussions (aws#2575)

Author: khushail

.github/workflows/handle-stale-discussions.yml

@@ -0,0 +1,18 @@
+name: HandleStaleDiscussions
+on:
+  schedule:
+    - cron: '0 */4 * * *'
+  discussion_comment:
+    types: [created]
+
+jobs:
+  handle-stale-discussions:
+    name: Handle stale discussions
+    runs-on: ubuntu-latest
+    permissions:
+      discussions: write
+    steps:
+      - name: Stale discussions action
+        uses: aws-github-ops/handle-stale-discussions@v1
+        env:
+          GITHUB_TOKEN:  ${{secrets.GITHUB_TOKEN}}