"npm test" fails when running on Node.js 10+

[onebytegone]

When using Node.js 10 or greater, npm test will fail with the error:

$ npm test
> @silvermine/[email protected] test /home/travis/build/silvermine/lambda-utils
> istanbul cover ./node_modules/.bin/_mocha -- -R spec 'tests/**/*.test.js'
  event-unwrappers/s3-in-sns
/home/travis/build/silvermine/lambda-utils/node_modules/istanbul/lib/command/common/run-with-cover.js:239
                        console.error('=============================================================================');
                                ^
TypeError: console.error is not a function
    at process.<anonymous> (/home/travis/build/silvermine/lambda-utils/node_modules/istanbul/lib/command/common/run-with-cover.js:239:33)
    at Object.onceWrapper (events.js:273:13)
    at process.emit (events.js:187:15)
npm ERR! Test failed.  See above for more details.
The command "npm test" exited with 1.

Example: https://travis-ci.org/silvermine/lambda-utils/jobs/458534214

[onebytegone]

This commit might be of help: silvermine/apigateway-utils@89d9eae