Update google-auth-library (and others)

[csb324]

Fixes #228!

It looked like google-auth-library was about five major versions behind, and google had made some changes to how it all worked. So I...

• updated google-auth-library,
• then updated the relevant files to use the new google-auth-library interfaces
• then updated the tests so that the tests will reveal this kind of problem in the future
• ... which led to a teeny refactor of the gsheets.ts file (which was mostly done to make stubbing easier).

And now the package is working for me again! The one thing I couldn't solve is that the linter doesn't like my async arrow function test, so I imagine the CI tests here will fail. I couldn't figure out what that was about, considering the tests work, and the google-oauth test suite uses the same syntax without complaining.

[denar90]

Hey @csb324. Thank you for the PR 👍 Do you think we can have failing CI fixed? I'll be more than happy to mere your fix :)

[nathanmillar16]

Hi. I left a comment on the PR. Was you able to write to a google-sheet @csb324 ? Thanks