Update welcome.yml. Added jobs.

Added a "build" join to my workflow.

Author: Chau-Nguyen-Developer

.github/workflows/welcome.yml

@@ -1,9 +1,10 @@
-//Give my workflow a name
 name: Post welcome comment
-//My workflow will execute whenever someone opens a pull request in my repository
 on:
   pull_request:
     types: [opened]
-  //Assigns the workflow permissions to operate on the repository  
   permissions:
-    pull-requests: write //gives the workflow permission to write to pull requests.
+    pull-requests: write
+  jobs:
+    build:
+      name: Post welcome comment
+      runs-on: ubuntu-latest