feat: promote to GA (#311)

Release-As: 1.0.0

Author: Neenu1995

.repo-metadata.json

@@ -4,7 +4,7 @@
     "product_documentation": "https://cloud.google.com/ai-platform-notebooks",
     "api_description": "is a managed service that offers an integrated and secure JupyterLab environment for data scientists and machine learning developers to experiment, develop, and deploy models into production. Users can create instances running JupyterLab that come pre-installed with the latest data science and machine learning frameworks in a single click.",
     "client_documentation": "https://cloud.google.com/java/docs/reference/google-cloud-notebooks/latest/history",
-    "release_level": "preview",
+    "release_level": "stable",
     "transport": "grpc",
     "language": "java",
     "repo": "googleapis/java-notebooks",

README.md

@@ -8,9 +8,6 @@ Java idiomatic client for [AI Platform Notebooks][product-docs].
 - [Product Documentation][product-docs]
 - [Client Library Documentation][javadocs]
 
-> Note: This client is a work-in-progress, and may occasionally
-> make backwards-incompatible changes.
-
 
 ## Quickstart
 
@@ -133,9 +130,6 @@ and on [google-cloud-java][g-c-j].
 This library follows [Semantic Versioning](http://semver.org/).
 
 
-It is currently in major version zero (``0.y.z``), which means that anything may change at any time
-and the public API should not be considered stable.
-
 
 ## Contributing
 
@@ -176,7 +170,7 @@ Java is a registered trademark of Oracle and/or its affiliates.
 [kokoro-badge-link-4]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-notebooks/java8-win.html
 [kokoro-badge-image-5]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-notebooks/java11.svg
 [kokoro-badge-link-5]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-notebooks/java11.html
-[stability-image]: https://img.shields.io/badge/stability-preview-yellow
+[stability-image]: https://img.shields.io/badge/stability-stable-green
 [maven-version-image]: https://img.shields.io/maven-central/v/com.google.cloud/google-cloud-notebooks.svg
 [maven-version-link]: https://search.maven.org/search?q=g:com.google.cloud%20AND%20a:google-cloud-notebooks&core=gav
 [authentication]: https://github.com/googleapis/google-cloud-java#authentication