fix: owlbot post-processor should generate README (#1154) (#504)

Fixes #1146
Fixes #1147
Source-Link: googleapis/synthtool@387851d
Post-Processor: gcr.io/repo-automation-bots/owlbot-java:latest@sha256:69045edb77ff7c78fdfad02eae2b4493b2c358cd9778ab5b6dba0c2b578df0ec

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/repo-automation-bots/owlbot-java:latest
-  digest: sha256:2e88a4a7fe3377cf8de1fa5982134f6ef2768980fa2f94edcc1ba6604ae2e7ca
+  digest: sha256:69045edb77ff7c78fdfad02eae2b4493b2c358cd9778ab5b6dba0c2b578df0ec

README.md

@@ -144,10 +144,50 @@ To get help, follow the instructions in the [shared Troubleshooting document][tr
 
 Natural Language uses gRPC for the transport layer.
 
-## Java Versions
+## Supported Java Versions
 
 Java 7 or above is required for using this client.
 
+Google's Java client libraries,
+[Google Cloud Client Libraries][cloudlibs]
+and
+[Google Cloud API Libraries][apilibs],
+follow the
+[Oracle Java SE support roadmap][oracle]
+(see the Oracle Java SE Product Releases section).
+
+### For new development
+
+In general, new feature development occurs with support for the lowest Java
+LTS version covered by  Oracle's Premier Support (which typically lasts 5 years
+from initial General Availability). If the minimum required JVM for a given
+library is changed, it is accompanied by a [semver][semver] major release.
+
+Java 11 and (in September 2021) Java 17 are the best choices for new
+development.
+
+### Keeping production systems current
+
+Google tests its client libraries with all current LTS versions covered by
+Oracle's Extended Support (which typically lasts 8 years from initial
+General Availability).
+
+#### Legacy support
+
+Google's client libraries support legacy versions of Java runtimes with long
+term stable libraries that don't receive feature updates on a best efforts basis
+as it may not be possible to backport all patches.
+
+Google provides updates on a best efforts basis to apps that continue to use
+Java 7, though apps might need to upgrade to current versions of the library
+that supports their JVM.
+
+#### Where to find specific information
+
+The latest versions and the supported Java versions are identified on
+the individual GitHub repository `github.com/GoogleAPIs/java-SERVICENAME`
+and on [google-cloud-java][g-c-j].
+
 ## Versioning
 
 
@@ -208,3 +248,9 @@ Java is a registered trademark of Oracle and/or its affiliates.
 [enable-api]: https://console.cloud.google.com/flows/enableapi?apiid=language.googleapis.com
 [libraries-bom]: https://github.com/GoogleCloudPlatform/cloud-opensource-java/wiki/The-Google-Cloud-Platform-Libraries-BOM
 [shell_img]: https://gstatic.com/cloudssh/images/open-btn.png
+
+[semver]: https://semver.org/
+[cloudlibs]: https://cloud.google.com/apis/docs/client-libraries-explained
+[apilibs]: https://cloud.google.com/apis/docs/client-libraries-explained#google_api_client_libraries
+[oracle]: https://www.oracle.com/java/technologies/java-se-support-roadmap.html
+[g-c-j]: http://github.com/googleapis/google-cloud-java