Replace deprecated RxJava methods.

[viniciussoares]

As mentioned by @jemmaSlater here, there was a bunch of deprecated methods within the existing code, most of them related to the old RxJavaPlugins api.

ReactiveX/RxJava#4007

[ribotaccounts]

Can one of the admins verify this patch?

[jemmaSlater]

Thanks for updating these, I'm happy to merge them in without any changes!

However, the deprecated methods I was referring to previously in relation to the Mockito update were as follows:

• org.mockito.runners.MockitoJUnitRunner -> The import now needs to be changed to org.mockito.junit.MockitoJUnitRunner
• anyListOf(java.lang.Class<T>) -> Used in a couple of our tests, now deprecated will need to be changed to use the anyList() method. eg: anyListOf(Ribot.class) -> ArgumentMatchers.<Ribot>anyList()

Feel free to make another pull request with these updates if you like, but thanks for updating the RxJavaPlugins which were also on our todo list! 👍

[viniciussoares]

Happy to help :) The todo list is public? Maybe i can help.

[jemmaSlater]

No public todo list I'm afraid - just generally trying to keep everything up to date, and was aware RxJavaPlugins needed updating!