docs: Update readme (#698)

Author: dpcollins-google

pubsublite-beam-io/README.md

@@ -9,7 +9,7 @@ into the allowlist and launch the pipeline with `--experiments=use_runner_v2`.
 <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>pubsublite-beam-io</artifactId>
-   <version>0.14.2</version>
+   <version>0.15.0</version>
 </dependency>
 ```
 1. Create a topic using [`gcloud pubsub lite-topics create`](https://cloud.google.com/sdk/gcloud/reference/pubsub/lite-topics/create)