No support for custom branches note in README.

README.md

@@ -1,7 +1,7 @@
 # dependency-review-action
 
 This action scans your pull requests for dependency changes, and will
-raise an error if any vulnerabilities or invalid licenses are being introduced. The action is supported by an [API endpoint](https://docs.github.com/en/rest/reference/dependency-graph#dependency-review) that diffs the dependencies between any two revisions.
+raise an error if any vulnerabilities or invalid licenses are being introduced. The action is supported by an [API endpoint](https://docs.github.com/en/rest/reference/dependency-graph#dependency-review) that diffs the dependencies between any two revisions on your default branch.
 
 The action is available for all public repositories, as well as private repositories that have GitHub Advanced Security licensed.