docs: add gen2 to Google Cloud Run deploy (#1191)

Co-authored-by: Alejandro Santiago <[email protected]>

Author: ryzizub

docs/docs/deploy/google-cloud-run.md

@@ -55,6 +55,10 @@ gcloud run deploy [SERVICE_NAME] \
 - `[PROJECT_ID]`: The ID of the Google Cloud project
 - `[REGION]`: The GCP region you wish to deploy to (ex: us-central1)
 
+:::caution
+There is an ongoing [issue](https://github.com/google/gvisor/issues/7331) that is preventing Dart Unix Sockets from working correctly in the gen1 version of the [Cloud Run execution environment](https://cloud.google.com/run/docs/about-execution-environments). In that case, it is recommended to deploy to gen2 by adding `--execution-environment=gen2`.
+:::
+
 Running this command will do three things:
 
 - Upload the code in the `/build` directory