add chatOpts help message workflow

Signed-off-by: hlts2 <[email protected]>

.github/workflows/chatops-help.yml

@@ -0,0 +1,33 @@
+name: "ChatOps help"
+
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  dump_contexts_to_log:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ./.github/actions/dump-context
+
+  print-help:
+    name: "print ChatOps help message"
+    runs-on: ubuntu-latest
+    steps:
+      - name: comment to PR
+        run: |
+          curl -o chatops_commands.md https://raw.githubusercontent.com/vdaas/vald/main/.github/chatops_commands.md
+          BODY=`cat chatops_commands.md | sed ':a;N;$!ba;s/\n/\\\\n/g'`
+          curl --include --verbose --fail \
+          -H "Accept: application/json" \
+          -H "Content-Type:application/json" \
+          -H "Authorization: token ${GITHUB_TOKEN}" \
+          --request POST \
+          --data "{\"body\": \"**[CHATOPS:HELP]** ChatOps commands.\\n${BODY}\"}" \
+          $API_URL
+        env:
+          GITHUB_TOKEN: ${{ secrets.DISPATCH_TOKEN }}
+          API_URL: ${{ github.event.pull_request.comments_url }}
+          PR_NUM: ${{ github.event.issue.number }}
+