Gradle methods not updated for "getting-started-grpc"

## In which file did you encounter the issue?
https://github.com/GoogleCloudPlatform/java-docs-samples/tree/main/endpoints/getting-started-grpc
While running: ```./gradlew build```

## Did you change the file? If so, how?
Did not change the file.

## Describe the issue
I tried setting up the package to try out running the grpc example locally. The first command fails.
The reason is that the gradle methods are not updated to the newer version.

(Tried to fix it myself, but everyone trying this out will run into this, and it is a waste of time for everyone fixing the methods.)

Thanks!