update github actions docs

Author: nicktrn

docs/github-actions.mdx

@@ -130,6 +130,10 @@ When self-hosting, you will have to take a few additional steps:
 - Add your registry credentials to the GitHub secrets.
 - Use the `--self-hosted` and `--push` flags when deploying.
 
+<Tip>
+  If you're self-hosting v4, the `--self-hosted` and `--push` flags are **NOT** needed.
+</Tip>
+
 Other than that, your GitHub action file will look very similar to the one above:
 
 <CodeGroup>