Upgrade Mockito dependency to version 2

[suztomo]

Please answer these questions before submitting your issue.

What version of gRPC are you using?

io.grpc:grpc-testing:1.17.1

What did you expect to see?

To use Mockito version 2.

As of now grpc-java project uses mockito 1.9.X. The last release of 1.9.X is 1.9.10 in 2014.

grpc-java/build.gradle

Line 236 in ef6b616

mockito: 'org.mockito:mockito-core:1.9.5',

Would you upgrade the dependency to mockito 2.24.0?
Mockito upgrade guilde from 1.10 to 2.X

Background

I'm trying to clean up grpc-related conflicting/outdated dependencies. (Example spring-cloud/spring-cloud-sleuth#1186)

[carl-mastrangelo]

In progress in #5219

We can't use 2 yet, as the dependency is not available yet inside.

[suztomo]

Thank you for response. I'm in no hurry. I will check the status again later (Maybe in April)