Eslint v7 is incompatible with node 8 and eslint-plugin-import

[mleguen]

@bcoe Due to #1656, we have warnings now in npm install as eslint-plugin-import is not yet compatible with eslint v7:

npm WARN eslint-plugin-react@7.14.3 requires a peer of eslint@^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN eslint-plugin-import@2.20.1 requires a peer of eslint@2.x - 6.x but none is installed. You must install peer dependencies yourself.

Nothing seems to be broken in linting however.

Upgrading to eslint-plugin-import@2.20.2 does not change anything.

[mleguen]

Eslint 7.2.0 no longer supports node 8, so our tests on master are now failing on an optional catch binding.