Previously only 65 rules were enabled, since the `eslint:recommended`
and `plugin:react/recommended` entries in `extends` had no effect,
since when using ESLint's API rather than CLI, the options must be
passed inside the `baseConfig` property instead.
This commit corrects the usage of `extends` and switches us to AirBnb's
React ESLint preset rather than manually opting into rules:
https://github.com/airbnb/javascript
Even with the temporarily disabled rules (which can be gradually fixed
in the future), there are now over 200 ESLint rules enabled, giving
a significant increase in coverage.
Note: We're having to use v15 of `eslint-config-airbnb` rather than v16
until we update to newer Neutrino, since the latest preset has dropped
support for the ESLint v3 that comes with Neutrino 4.
Now that the group package PR title and commit messages have been
adjusted upstream, our config no longer needs to override them. See:
1e4bebe627
[skip ci]
Ed Morley
renovate[bot]