Bump protobuf hash for Bazel

bazel/grpc_deps.bzl

@@ -85,8 +85,8 @@ def grpc_deps():
     if "com_google_protobuf" not in native.existing_rules():
         native.http_archive(
             name = "com_google_protobuf",
-            strip_prefix = "protobuf-2761122b810fe8861004ae785cc3ab39f384d342",
-            url = "https://github.com/google/protobuf/archive/2761122b810fe8861004ae785cc3ab39f384d342.tar.gz",
+            strip_prefix = "protobuf-b5fbb742af122b565925987e65c08957739976a7",
+            url = "https://github.com/google/protobuf/archive/b5fbb742af122b565925987e65c08957739976a7.tar.gz",
         )
 
     if "com_github_google_googletest" not in native.existing_rules():