feat: promote to 1.0.0 (#16)

Release-As: 1.0.0

.repo-metadata.json

@@ -4,7 +4,7 @@
   "product_documentation": "n/a",
   "api_description": "n/a",
   "client_documentation": "https://googleapis.dev/java/proto-google-iam-v1/latest/index.html",
-  "release_level": "beta",
+  "release_level": "ga",
   "transport": "grpc",
   "requires_billing": true,
   "language": "java",

README.md

@@ -7,9 +7,6 @@ Java protobuf classes for IAM Policy.
 
 - [Client Library Documentation][javadocs]
 
-> Note: This client is a work-in-progress, and may occasionally
-> make backwards-incompatible changes.
-
 ## Java Versions
 
 Java 7 or above is required for using this client.
@@ -56,7 +53,7 @@ Apache 2.0 - See [LICENSE][license] for more information.
 [kokoro-badge-link-4]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-iam/java8-win.html
 [kokoro-badge-image-5]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-iam/java11.svg
 [kokoro-badge-link-5]: http://storage.googleapis.com/cloud-devrel-public/java/badges/java-iam/java11.html
-[stability-image]: https://img.shields.io/badge/stability-beta-yellow
+[stability-image]: https://img.shields.io/badge/stability-ga-green
 [maven-version-image]: https://img.shields.io/maven-central/v/com.google.api.grpc/proto-google-iam-v1.svg
 [maven-version-link]: https://search.maven.org/search?q=g:com.google.api.grpc%20AND%20a:proto-google-iam-v1&core=gav
 [authentication]: https://github.com/googleapis/google-cloud-java#authentication