[CI] Lock pathspec major version

Author: donbarbos

requirements-tests.txt

@@ -10,7 +10,7 @@ aiohttp==3.13.2
 grpcio-tools>=1.66.2; python_version < "3.14" # For grpc_tools.protoc
 mypy-protobuf==4.0.0
 packaging==25.0
-pathspec>=0.11.1
+pathspec>=0.11.1,<1.0.0
 pre-commit
 # Required by create_baseline_stubs.py. Must match .pre-commit-config.yaml.
 ruff==0.14.10