chore(deps): bump io.grpc:grpc-stub from 1.64.0 to 1.68.1

Bumps [io.grpc:grpc-stub](https://github.com/grpc/grpc-java) from 1.64.0 to 1.68.1.
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](grpc/grpc-java@v1.64.0...v1.68.1)

---
updated-dependencies:
- dependency-name: io.grpc:grpc-stub
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

rdfc-orchestrator/build.gradle.kts

@@ -18,7 +18,7 @@ dependencies {
   // gRPC
   implementation("io.grpc:grpc-netty:1.64.0")
   implementation("io.grpc:grpc-protobuf:1.64.0")
-  implementation("io.grpc:grpc-stub:1.64.0")
+  implementation("io.grpc:grpc-stub:1.68.1")
   implementation("io.grpc:grpc-kotlin-stub:1.4.1")
   implementation("com.google.protobuf:protobuf-kotlin:4.27.1")