MNT: (deps): Bump protobuf from 3.20.1 to 5.28.3 in /ci

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 3.20.1 to 5.28.3.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v3.20.1...v5.28.3)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

ci/requirements.txt

@@ -1,5 +1,5 @@
 beautifulsoup4==4.12.3
 numpy==1.26.0
 pandas==2.2.3
-protobuf==5.28.2
+protobuf==5.28.3
 requests==2.28.1