Bump protobuf from 5.26.1 to 5.29.6 in /py

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 5.26.1 to 5.29.6.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Commits](https://github.com/protocolbuffers/protobuf/commits)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 5.29.6
  dependency-type: direct:production
...

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

Author: dependabot[bot]

py/requirements.txt

@@ -2,7 +2,7 @@ base58==2.1.1
 click==8.1.7
 markdown-it-py==3.0.0
 mdurl==0.1.2
-protobuf==5.26.1
+protobuf==5.29.6
 Pygments==2.17.2
 rich==13.7.1
 sentencepiece==0.2.0