upgrade protobuf to 6.33.5 (fix security problem)

Cause: protobuf affected by a JSON recursion depth bypass:

A denial-of-service (DoS) vulnerability exists in google.protobuf.json_format.ParseDict() in Python, where the max_recursion_depth limit can be bypassed when parsing nested google.protobuf.Any messages.

Due to missing recursion depth accounting inside the internal Any-handling logic, an attacker can supply deeply nested Any structures that bypass the intended recursion limit, eventually exhausting Python’s recursion stack and causing a RecursionError.

src/protobuf_generated_python/google_auth_pb2.py

@@ -2,7 +2,7 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # NO CHECKED-IN PROTOBUF GENCODE
 # source: google_auth.proto
-# Protobuf Python Version: 6.33.4
+# Protobuf Python Version: 6.33.5
 """Generated protocol buffer code."""
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import descriptor_pool as _descriptor_pool
@@ -13,7 +13,7 @@ _runtime_version.ValidateProtobufRuntimeVersion(
     _runtime_version.Domain.PUBLIC,
     6,
     33,
-    4,
+    5,
     '',
     'google_auth.proto'
 )