clarify github-token usage

README.md

@@ -49,7 +49,7 @@ Optional fields:
 - `fail-on-sast-scan`: Determines wether Aikido should block on new SAST issues. This is available in all [paid plans](https://www.aikido.dev/pricing).
 - `fail-on-iac-scan`: Determines wether Aikido should block on new Infrastructure as Code issues. This is available in all [paid plans](https://www.aikido.dev/pricing).
 - `post-scan-status-comment`: Let Aikido post a comment on the PR (when in PR context) with the latest scan status and a link to the scan results.
-- `github-token`: Optional. If the default `${{ secrets.GITHUB_TOKEN }}` environment token does not have write capabilities, Aikido needs a PAT with specific permissions to read and write comments in a PR.
+- `github-token`: Must be set only if you want Aikido to post a comment on the PR. If the default `${{ secrets.GITHUB_TOKEN }}` environment token does not have write capabilities, Aikido needs a PAT with specific permissions to read and write comments in a PR.
 
 
 ## Contributing