Fix Maven dependency convergence errors

[ivanauth]

Summary

Resolves dependency conflicts introduced in #151 that cause maven-enforcer-plugin convergence failures for downstream Maven users.

Changes

• Add exclusion for proto-google-common-protos from grpc-protobuf to prevent version 2.59.2 from conflicting with 2.61.3
• Add exclusions to protovalidate and pgv-java-stub for transitive dependencies that conflict with SDK versions
• Explicitly declare aligned versions:
  • protobuf-java: 4.32.1
  • protobuf-java-util: 4.32.1
  • proto-google-common-protos: 2.61.3
  • gson: 2.11.0
  • re2j: 1.8

Testing

• Build completed successfully: ./gradlew clean build
• Verified dependency convergence with ./gradlew dependencies --configuration runtimeClasspath
• All conflicting dependencies now resolve to single versions

Fixes dependency convergence errors reported by users upgrading to v1.5.2.