Remove welcome action (#400)

.github/workflows/welcome.yaml

@@ -1,31 +0,0 @@
-name: Welcome for First Issue or Pull Request
-
-on:
-  pull_request:
-    types:
-    - opened
-  issues:
-    types:
-    - opened
-
-jobs:
-  welcome:
-    runs-on: ubuntu-latest
-
-    steps:
-    - name: Welcome for First Issue or Pull Request
-      uses: actions/first-interaction@v1
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        issue-message: |
-          ### :wave: Welcome! Looks like this is your first issue.
-
-          Hey, thanks for your contribution! Please give us a bit of time to review it. 😄
-
-          **Be sure to follow the issue template!**
-        pr-message: |
-          ### :wave: Welcome! Looks like this is your first pull request.
-
-          Hey, thanks for your contribution! Please give us a bit of time to review it. 😄
-
-          **Please check out our contributing guidelines.**