dev: welcome first-time contributors

.github/workflows/welcome.yml

@@ -0,0 +1,12 @@
+name: Auto message
+on: [pull_request, issues]
+jobs:
+  build:
+    name: Hello new contributor
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/first-interaction@v1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          issue-message: "Hey, thank you for opening your first Issue ! 🙂"
+          pr-message: "Hey, thank you for opening your first Pull Request !"