Upgrade mockwebserver to 3.8.1 from OkHttp distribution

[apjanke]

This library uses an old version of mockwebserver from back when it was a standalone project. It has since been folded in to OkHttp, which this project also uses. The new mockwebserver is at com.squareup.okhttp3:mockwebserver:3.8.1.

From their old Google Code website:

Shall we upgrade to the new version from OkHttp? It looks like this project is keeping current on all its other dependencies.

This PR accomplishes the upgrade by changing the mockwebserver dependency to the new com.squareup.okhttp3:mockwebserver:3.8.1 one, and updating the code to handle the mockwebserver API changes between 20130706 and 3.8.1.

Tests pass locally for me.

[domesticmouse]

Can you please run ./gradlew googleFormatJava? This PR looks like it will fail the format check due to the ordering of the imports. Thanks!

[apjanke]

I manually amended the code to comply with the format check, based on my reading of Google's Java Style Guide section on import statements.

Also rebased on master.

When I run ./gradlew googleFormatJava, I just get an error about it being an undefined task.

$ ./gradlew googleFormatJava

FAILURE: Build failed with an exception.

* What went wrong:
Task 'googleFormatJava' not found in root project 'google-maps-services-java'.

* Try:
Run gradlew tasks to get a list of available tasks. Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED in 0s

Do I need to install some other library or something to get this to work? I read the build instructions, and don't see anything that looks relevant.

[domesticmouse]

Whacky. I'll land this PR as is and fix up any issues. Thanks!

[apjanke]

You're welcome. And thanks!

[apjanke]

Oh, my problem is obvious now: It's ./gradlew googleJavaFormat, not ./gradlew googleFormatJava. It works for me now that I got the name right.