Fix annotation processor warning (#560)

Author: slinkydeveloper

sdk-api-gen/src/main/java/dev/restate/sdk/gen/ServiceProcessor.java

@@ -29,7 +29,6 @@
 import javax.tools.StandardLocation;
 
 @SupportedAnnotationTypes("*")
-@SupportedSourceVersion(SourceVersion.RELEASE_17)
 public class ServiceProcessor extends AbstractProcessor {
 
   private HandlebarsTemplateEngine serviceDefinitionFactoryCodegen;
@@ -158,6 +157,11 @@ public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment
     return false;
   }
 
+  @Override
+  public SourceVersion getSupportedSourceVersion() {
+    return SourceVersion.latestSupported();
+  }
+
   public static Path readOrCreateResource(Filer filer, String file) throws IOException {
     try {
       FileObject fileObject = filer.getResource(StandardLocation.CLASS_OUTPUT, "", file);