greetings: enable workflow to run from workflow dispatch

this would make testing workflow easier and also convenient for manual greetings

.github/workflows/greetings.yml

@@ -1,6 +1,6 @@
 name: Greetings
 
-on: [pull_request, issues]
+on: [pull_request, issues, workflow_dispatch]
 
 jobs:
   greeting:
@@ -13,4 +13,4 @@ jobs:
       with:
         repo-token: ${{ secrets.GITHUB_TOKEN }}
         issue-message: 'Hey, @${{ github.actor }} welcome to JEE Counsellor repository.🎊 Thank you so much for taking the time to point this out.🙌'
-        pr-message: 'Hey, @${{ github.actor }} welcome to JEE Counsellor repository.🎊 Thank you so much for taking the effort to make our project better! 🙌 Keep making such awesome contributions!'
+        pr-message: 'Hey, @${{ github.actor }} welcome to JEE Counsellor repository.🎊 Thank you so much for taking the effort to make our project better! 🙌 Keep making such awesome contributions!'