Finish dependency revisions for new instrumentation libs

[mannodermaus]

I feel like the integration is really smooth now. Once this is done, I'll test against another reference project through the actual Maven coordinates, and after that we should be good to go with the inaugural release. That's also when I'll attend to writing the guides on this stuff, too.

Final artifacts:

• de.mannodermaus.junit5:android-test-core
• de.mannodermaus.junit5:android-test-runner

Final integration:

dependencies {
  // Required for all tests
  androidTestImplementation("androidx.test:runner:...")
  // If you want...
  androidTestImplementation("androidx.test.espresso:espresso-core:...")
  // Required for JUnit 5 tests
  androidTestImplementation("org.junit.jupiter:junit-jupiter-api:...")

  // NEW: Required for JUnit 5 instrumentation tests
  androidTestImplementation("de.mannodermaus.junit5:android-test-core:...")
  androidTestRuntimeOnly("de.mannodermaus.junit5:android-test-runner:...")
}