docs(node): support "stable"/"preview" release level (#1312) (#581)

Author: gcf-owl-bot[bot]

handwritten/logging-bunyan/.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-nodejs:latest
-  digest: sha256:ba3f2990fefe465f89834e4c46f847ddb141afa54daa6a1d462928fa679ed143
+  digest: sha256:5ed10ba99cd1ea8c3a0f29b4c53e8a2723a101952705baed6b61783111c64c1c

handwritten/logging-bunyan/README.md

@@ -268,6 +268,8 @@ are addressed with the highest priority.
 
 
 
+
+
 More Information: [Google Cloud Platform Launch Stages][launch_stages]
 
 [launch_stages]: https://cloud.google.com/terms/launch-stages