Upgrade build to Node 10

[yurishkuro]

Code coverage breaks with Node 8

$ yarn global add codecov
yarn global v1.22.5
[1/4] Resolving packages...
a@^4.0.0ap@0.0.1[2/4] Fetching packages...
error teeny-request@7.0.1: The engine "node" is incompatible with this module. Expected version ">=10". Got "8.17.0"
error Found incompatible module.
info Visit https://yarnpkg.com/en/docs/cli/global for documentation about this command.
after_success.2
0.10s$ codecov
codecov: command not found

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@fd21606). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #649   +/-   ##
=========================================
  Coverage          ?   93.74%           
=========================================
  Files             ?      227           
  Lines             ?     5902           
  Branches          ?     1483           
=========================================
  Hits              ?     5533           
  Misses            ?      328           
  Partials          ?       41           

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