Update the proto files from upsteam protobuf.

Using commit 87f1d9e2f66bf6028ef416481ada1602cbfc0bc8

Author: thomasvl

Protos/google/protobuf/unittest_custom_options.proto

@@ -45,6 +45,7 @@ option py_generic_services = true;
 // A custom file option (defined below).
 option (file_opt1) = 9876543210;
 
+import "google/protobuf/any.proto";
 import "google/protobuf/descriptor.proto";
 
 // We don't put this in a package within proto2 because we need to make sure
@@ -329,6 +330,9 @@ message Aggregate {
 
   // An embedded message set
   optional AggregateMessageSet mset = 5;
+
+  // An any
+  optional google.protobuf.Any any = 6;
 }
 
 // Allow Aggregate to be used as an option at all possible locations
@@ -376,6 +380,12 @@ option (fileopt) = {
       s: 'EmbeddedMessageSetElement'
     }
   }
+
+  any {
+    [type.googleapis.com/protobuf_unittest.AggregateMessageSetElement] {
+      s: 'EmbeddedMessageSetElement'
+    }
+  }
 };
 
 message AggregateMessage {