Bump feature version to 1.2.0 (#367)

Author: vancexu

src/main/java/com/uber/cadence/internal/Version.java

@@ -43,7 +43,7 @@ public class Version {
    * support. This can be used for client capibility check, on Cadence server, for backward
    * compatibility Format: MAJOR.MINOR.PATCH
    */
-  public static final String FEATURE_VERSION = "1.0.0";
+  public static final String FEATURE_VERSION = "1.2.0";
 
   static {
     // Load version from version.properties generated by Gradle into build/resources/main directory.