build(deps): bump protobuf from 6.31.0 to 6.31.1 in /samples/snippets

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 6.31.0 to 6.31.1.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v6.31.0...v6.31.1)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 6.31.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

samples/snippets/requirements.txt

@@ -2,7 +2,7 @@ google-cloud-pubsub==2.29.0
 avro==1.12.0
 protobuf===4.24.4; python_version == '3.7'
 protobuf===5.29.4; python_version == '3.8'
-protobuf==6.31.0; python_version >= '3.9'
+protobuf==6.31.1; python_version >= '3.9'
 avro==1.12.0
 opentelemetry-api===1.22.0; python_version == '3.7'
 opentelemetry-sdk===1.22.0; python_version == '3.7'