Update supported java version to 11

Author: s-soroosh

operator-framework/src/main/java/io/javaoperatorsdk/operator/config/runtime/ControllerAnnotationProcessor.java

@@ -35,7 +35,7 @@
 import javax.tools.JavaFileObject;
 
 @SupportedAnnotationTypes("io.javaoperatorsdk.operator.api.Controller")
-@SupportedSourceVersion(SourceVersion.RELEASE_8)
+@SupportedSourceVersion(SourceVersion.RELEASE_11)
 @AutoService(Processor.class)
 public class ControllerAnnotationProcessor extends AbstractProcessor {