docs: adds docker community plugin that supports major, minor tagging

@semantic-release-plus/docker is a fork of semantic-release-docker
converted to typescript and 100% test coverage added.

@semantic-release-plus/docker also adds the functionality to support
major, minor tagging.

docs/extending/plugins-list.md

@@ -52,6 +52,9 @@
 - [semantic-release-docker](https://github.com/felixfbecker/semantic-release-docker)
   - `verifyConditions`: Verify that all needed configuration is present and login to the Docker registry.
   - `publish`: Tag the image specified by `name` with the new version, push it to Docker Hub and update the latest tag
+- [@semantic-release-plus/docker](https://github.com/semantic-release-plus/semantic-release-plus/tree/master/packages/plugins/docker)
+  - `verifyConditions`: Verify that all needed configuration is present and login to the configured docker registry.
+  - `publish`: Tag the image specified by `name` with the new version, push it to the configured docker registry and update the `latest`, `major`, `minor` tags based on the configuration settings.
 - [semantic-release-gcr](https://github.com/carlos-cubas/semantic-release-gcr)
   - `verifyConditions`: Verify that all needed configuration is present and login to the Docker registry
   - `publish`: Tag the image specified by `name` with the new version, push it to Docker Hub and update the latest tag