Roll back java_outer_classname

Author: yevhenii-nadtochii

proto/context/src/main/proto/spine/validation/events.proto

@@ -32,7 +32,7 @@ import "spine/options.proto";
 
 option (type_url_prefix) = "type.spine.io";
 option java_package = "io.spine.validation.event";
-option java_outer_classname = "RuleEventsProto";
+option java_outer_classname = "EventsProto";
 option java_multiple_files = true;
 
 option (every_is).java_type = "io.spine.validation.event.RuleAdded";