Adds the current release as a GitHub label on the README. It links to the releases tab in GitHub. (#6625)

Signed-off-by: David Venable <dlv@amazon.com>

Author: dlvenable

README.md

@@ -1,5 +1,6 @@
 <img src="https://raw.githubusercontent.com/opensearch-project/data-prepper/main/docs/images/DataPrepper_auto.svg" height="64px" alt="OpenSearch Data Prepper">
 
+[![GitHub release](https://img.shields.io/github/v/release/opensearch-project/data-prepper?sort=semver)](https://github.com/opensearch-project/data-prepper/releases)
 [![codecov](https://codecov.io/gh/opensearch-project/data-prepper/branch/main/graph/badge.svg?token=IS7GOIY622)](https://codecov.io/gh/opensearch-project/data-prepper)
 # OpenSearch Data Prepper