Updated readme to show 2.1.7 version (#413)

README.md

@@ -73,7 +73,7 @@ If you are using Maven, add the following dependency.
 <dependency>
     <groupId>com.microsoft.azure</groupId>
     <artifactId>spring-data-cosmosdb</artifactId>
-    <version>2.0.3</version>
+    <version>2.1.7</version>
 </dependency>
 ```