build(deps): bump protobuf from 5.26.1 to 5.29.5 (#4641)

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 5.26.1 to 5.29.5.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v5.26.1...v5.29.5)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 5.29.5
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs-requirements.txt

@@ -25,4 +25,4 @@ opentracing~=2.2.0
 thrift~=0.10
 wrapt>=1.0.0,<2.0.0
 markupsafe~=2.0
-protobuf==5.26.1
+protobuf==5.29.5

opentelemetry-proto/test-requirements.txt

@@ -3,7 +3,7 @@ importlib-metadata==6.11.0
 iniconfig==2.0.0
 packaging==24.0
 pluggy==1.5.0
-protobuf==5.26.1
+protobuf==5.29.5
 py-cpuinfo==9.0.0
 pytest==7.4.4
 tomli==2.0.1