Fix 'TypeError: _browserslist.findConfigFile is not a function'

[nifgraup]

What:

I remove browserslist override which was causing errors on: npm run setup -s

Why:

Have to build.

How:

removed pin in package.json

Checklist:

• N/A [ ] Documentation added to the
  docs site
• N/A [ ] Tests
• N/A [ ] TypeScript definitions updated
• [ x] Ready to be merged
  

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[eps1lon]

Have you checked why we added this? It used to ensure we always target the same syntax level. Changing it randomly on publish is unsafe since we might produce syntax that's only valid for newer Node.js/Browser versions i.e. a breaking change.

[nifgraup]

It was originally added in #1169 to avoid parsing error by Acorn < 7.3.0 (the Acorn JS parser is used by Webpack). Since then Node.js 12 has been dropped #1207 which similarly does not support Nullish coalescing like Acorn < 7.3.0.

I myself do similar thing as the reporter in #1169, use webpack to bundle the tests and run them in a browser. That webpack configuration sets the target of browsers to run the tests in.

Is webpack 4 (Acorn 6) within the support matrix?