[eslint-config-airbnb] Update react/sort-comp rule to allow static variables

[alexplumb]

As of eslint-plugin-react@7.15.0, the static-methods rule for react/sort-comp has seen a breaking change: it's been split into static-methods and static-variables. See the relevant pull request

Please change the rule for react/sort-comp to allow for static variables like so:

order: [
        'static-variables',
        'static-methods',
        'instance-variables',
        'lifecycle',
        '/^on.+$/',
        'getters',
        'setters',
        '/^(get|set)(?!(InitialState$|DefaultProps$|ChildContext$)).+$/',
        'instance-methods',
        'everything-else',
        'rendering',
      ],

[ljharb]

It's not a breaking change; static-methods never checked what static-variables checks. Adding that seems reasonable, though, and it'd be semver-patch since the airbnb guide currently doesn't allow using class fields at all.

[alexplumb]

Ah, makes sense. I upgraded to the newest version and suddenly it was complaining that my static variables had to be at the bottom of the class definition.