Pull gRPC from google-gax

[stephenplusplus]

Fixes #70

[stephenplusplus]

One sec, going to get rid of grpc.

[codecov]

Codecov Report

Merging #71 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #71   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files           8      8           
  Lines         849    849           
=====================================
  Hits          849    849

Impacted Files	Coverage Δ
src/index.js	100% <100%> (ø)	⬆️

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[alexander-fenster]

I wonder if we can check if 1.9.x works instead. They claim to have fixed all the issues that affected us and ask to verify. (I'm going to try it for google-gax and see if firestore works first)

[stephenplusplus]

That's good news. My latest change to this PR will pull gRPC from the google-gax package, so this should be a fix for now and a fix for when we upgrade to a new version.

[stephenplusplus]

Issue about when to upgrade gRPC: googleapis/gax-nodejs#188