Update protobuf requirement in /src/bindings/python

Updates the requirements on [protobuf](https://github.com/protocolbuffers/protobuf) to permit the latest version.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v3.18.1...v6.30.1)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

src/bindings/python/constraints.txt

@@ -21,5 +21,5 @@ h5py>=3.1.0,<3.14.0
 docopt~=0.6.2
 paddlepaddle==2.6.2
 tensorflow>=1.15.5,<2.18.0
-protobuf>=3.18.1,<6.0.0
+protobuf>=3.18.1,<7.0.0
 onnx==1.17.0