Delete greetings.yml

https://github.com/SpudGunMan/meshing-around/issues/346

.github/workflows/greetings.yml

@@ -1,21 +0,0 @@
-name: Greetings
-
-on:
-  issues:
-    types: [opened]
-  pull_request:
-    types: [opened]
-
-permissions:
-  issues: write
-  pull-requests: write
-
-jobs:
-  greeting:
-    name: Greet first-time contributors
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/first-interaction@v3
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
-          pr_message: "Thank you for your pull request!"