Do not require Ruby enum to be upper case

ruby/ext/google/protobuf_c/message.c

@@ -697,12 +697,6 @@ VALUE build_module_from_enumdesc(EnumDescriptor* enumdesc) {
        upb_enum_next(&it)) {
     const char* name = upb_enum_iter_name(&it);
     int32_t value = upb_enum_iter_number(&it);
-    // if (name[0] < 'A' || name[0] > 'Z') {
-    //   rb_raise(cTypeError,
-    //            "Enum value '%s' does not start with an uppercase letter "
-    //            "as is required for Ruby constants.",
-    //            name);
-    // }
     rb_define_const(mod, name, INT2NUM(value));
   }