fix: validate_description to run on bot commits.

Author: codeon

.github/workflows/validate-description.yml

@@ -1,7 +1,10 @@
 name: validate description
 
 on:
-  pull_request:
+  # pull_request_target is meant to run on bot commits. 
+  # Do check out and run code from the pull request's head commit. 
+  # It is suitable for this usecase as we are only looking at PR description. 
+  pull_request_target:
     types: [opened, synchronize, reopened, edited]
 
 jobs: