Update workflow

Author: thomaspinder

.github/workflows/pr_greeting.yml

@@ -13,8 +13,8 @@ jobs:
     steps:
       - uses: actions/[email protected]
         with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
-          pr-message: >+
+          repo_token: ${{ secrets.GITHUB_TOKEN }}
+          pr_message: >+
             Thank you for opening your first PR into GPJax!