[ObjC] Update generation to include the new closed enum information.

Also bump the generation version since the generate files require the newer
library version.

PiperOrigin-RevId: 488711994
diff --git a/objectivec/GPBTimestamp.pbobjc.m b/objectivec/GPBTimestamp.pbobjc.m
index 7d2276c..81bdcd9 100644
--- a/objectivec/GPBTimestamp.pbobjc.m
+++ b/objectivec/GPBTimestamp.pbobjc.m
@@ -79,7 +79,7 @@
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBTimestamp__storage_)
-                                         flags:(GPBDescriptorInitializationFlags)(GPBDescriptorInitializationFlag_UsesClassRefs | GPBDescriptorInitializationFlag_Proto3OptionalKnown)];
+                                         flags:(GPBDescriptorInitializationFlags)(GPBDescriptorInitializationFlag_UsesClassRefs | GPBDescriptorInitializationFlag_Proto3OptionalKnown | GPBDescriptorInitializationFlag_ClosedEnumSupportKnown)];
     #if defined(DEBUG) && DEBUG
       NSAssert(descriptor == nil, @"Startup recursed!");
     #endif  // DEBUG