Fixed @Api's javadocs

Author: webron

modules/swagger-annotations/src/main/java/com/wordnik/swagger/annotations/Api.java

@@ -59,6 +59,8 @@
      * <p/>
      * The `basePath` is derived automatically by Swagger. This property allows
      * overriding the default value if needed.
+     *
+     * @since 1.3.7
      */
     String basePath() default "";