Add the release badge for FHIR Engine library

README.md

@@ -14,7 +14,7 @@ The SDK is designed to support Android 21 (lollipop) and above. Android Studio 4
 ## Libraries
 The repository is organised into two main libraries, *engine* and *structured data capture*.
 
-### FHIR engine library
+### FHIR engine library [![Google Maven](https://badgen.net/maven/v/metadata-url/dl.google.com/dl/android/maven2/com/google/android/fhir/engine/maven-metadata.xml)](https://maven.google.com/web/index.html?#com.google.android.fhir:engine)
 This is the main library for building a mobile based clinical data repository using FHIR. It provides:
 - SQLite database for FHIR resources
 - APIs for accessing (create, read, update, and delete) FHIR resources in the database