Readme: Trigger only on "READY TO REVIEW" label (#18)

The current version of the workflow triggers on any label applied; we
only want this to trigger on "READY TO REVIEW" items in the reference workflow

However, in this repo we want every workflow to trigger so it's easier to debug.

Author: neonspectra

.github/workflows/code-review.yml

@@ -18,4 +18,4 @@ jobs:
         with:
           comment-pr: true
           upload-results: true
-          claude-api-key: ${{ secrets.CLAUDE_API_KEY }}
+          claude-api-key: ${{ secrets.CLAUDE_API_KEY }}

README.md

@@ -42,6 +42,7 @@ jobs:
         with:
           comment-pr: true
           claude-api-key: ${{ secrets.CLAUDE_API_KEY }}
+          require-label: 'READY TO REVIEW' # If this isn't set, the action will trigger any time *any* label is applied
 ```
 
 ## Security Considerations