use pull_request_target, add perms

- changed event trigger from pull_request to pull_request_target
- added permissions for contents: read, issues: write, pull-requests: write

Author: leemthompo

.github/workflows/docs-preview-comment.yml

@@ -1,9 +1,14 @@
 name: "Docs preview comment"
 
 on:
-  pull_request:
+  pull_request_target:
     types: [opened, reopened, synchronize]
 
+permissions:
+  contents: read
+  issues: write
+  pull-requests: write
+
 jobs:
   preview-links:
     runs-on: ubuntu-latest