build(deps): bump protobuf-java from 2.6.1 to 3.16.1 in /interface

Bumps [protobuf-java](https://github.com/protocolbuffers/protobuf) from 2.6.1 to 3.16.1.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/generate_changelog.py)
- [Commits](https://github.com/protocolbuffers/protobuf/compare/v2.6.1...v3.16.1

)

---
updated-dependencies:
- dependency-name: com.google.protobuf:protobuf-java
  dependency-type: direct:production
...

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