build: add GitHub actions

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Commits in this repo since last synth:
fc1381c build: add node@13 runtime (#599)
7ba1423 fix(deps): update dependency pprof to v1.3.0 (#595)
adca7f8 test: modernize mocha config (#589)
a6d331a chore: skip img.shields.io in docs test
2cb1fb1 chore(deps): update dependency @types/mocha to v7

Log from Synthtool

synthtool > Executing /tmpfs/src/git/autosynth/working_repo/synth.py.
On branch autosynth
nothing to commit, working tree clean
HEAD detached at FETCH_HEAD
nothing to commit, working tree clean
.eslintignore
.eslintrc.yml
.github/ISSUE_TEMPLATE/bug_report.md
.github/ISSUE_TEMPLATE/feature_request.md
.github/ISSUE_TEMPLATE/support_request.md
.github/PULL_REQUEST_TEMPLATE.md
.github/release-please.yml
.github/workflows/ci.yaml
.jsdoc.js
.kokoro/common.cfg
.kokoro/continuous/node10/common.cfg
.kokoro/continuous/node10/docs.cfg
.kokoro/continuous/node10/lint.cfg
.kokoro/continuous/node10/samples-test.cfg
.kokoro/continuous/node10/system-test.cfg
.kokoro/continuous/node10/test.cfg
.kokoro/continuous/node12/common.cfg
.kokoro/continuous/node12/test.cfg
.kokoro/continuous/node8/common.cfg
.kokoro/continuous/node8/test.cfg
.kokoro/docs.sh
.kokoro/lint.sh
.kokoro/presubmit/node10/common.cfg
.kokoro/presubmit/node10/docs.cfg
.kokoro/presubmit/node10/lint.cfg
.kokoro/presubmit/node10/samples-test.cfg
.kokoro/presubmit/node10/system-test.cfg
.kokoro/presubmit/node10/test.cfg
.kokoro/presubmit/node12/common.cfg
.kokoro/presubmit/node12/test.cfg
.kokoro/presubmit/node8/common.cfg
.kokoro/presubmit/node8/test.cfg
.kokoro/presubmit/windows/common.cfg
.kokoro/presubmit/windows/test.cfg
.kokoro/publish.sh
.kokoro/release/docs.cfg
.kokoro/release/docs.sh
.kokoro/release/publish.cfg
.kokoro/samples-test.sh
.kokoro/system-test.sh
.kokoro/test.bat
.kokoro/test.sh
.kokoro/trampoline.sh
.nycrc
.prettierignore
.prettierrc
CODE_OF_CONDUCT.md
CONTRIBUTING.md
LICENSE
README.md
codecov.yaml
renovate.json
samples/README.md
synthtool > Wrote metadata to synth.metadata.

[codecov]

Codecov Report

Merging #600 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #600   +/-   ##
=======================================
  Coverage   15.78%   15.78%           
=======================================
  Files           7        7           
  Lines       14406    14406           
  Branches       67       67           
=======================================
  Hits         2274     2274           
  Misses      12128    12128           
  Partials        4        4

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