Update welcome.yml

Got the typo

Author: Hugofbf21

.github/workflows/welcome.yml

@@ -9,7 +9,7 @@ jobs:
     name: Post welcome comment
     runs-on: ubuntu-latest
     steps:
-      - run: gh pr comment "${{PR_URL}}" --body "Welcome to the repository!"
+      - run: gh pr comment "$PR_URL" --body "Welcome to the repository!"
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          PR_URL: ${{ github.evennt.pull_request.html_url }}
+          PR_URL: ${{ github.event.pull_request.html_url }}