Remove github action-based greeting in favor of binny

.github/workflows/greetings.yml

@@ -1,12 +0,0 @@
-name: Greetings
-
-on: [pull_request]
-
-jobs:
-  greeting:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/first-interaction@v1
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        pr-message: 'Thank you for contributing to PursuedPyBear! Don''t forget to add yourself `CONTRIBUTORS.md`.'