Update master version to 2.1.1. (#339)

Signed-off-by: Pan Li <panli@microsoft.com>

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.microsoft.azure</groupId>
     <artifactId>spring-data-cosmosdb</artifactId>
-    <version>2.1.1.BUILD-SNAPSHOT</version>
+    <version>2.1.1</version>
 
     <name>Spring Data for Azure Cosmos DB SQL API</name>
     <description>Spring Data for Azure Cosmos DB SQL API</description>