Raise API version to 3

No interface changes, only internal changes in AFM executor.

Author: liry

gooddata-java-model/src/main/resources/GoodDataApiVersion

@@ -1 +1 @@
-2
+3

gooddata-java/src/test/groovy/com/gooddata/sdk/service/GoodDataIT.groovy

@@ -18,7 +18,7 @@ import static org.hamcrest.CoreMatchers.startsWith
 class GoodDataIT extends GoodDataITBase<GdcService> {
 
     private static final String USER_AGENT = 'customAgent/X.Y'
-    private static final String API_VERSION = '2'
+    private static final String API_VERSION = '3'
 
     @Override
     protected GoodDataSettings createGoodDataSettings() {