Migrate from v6 to v7

[filiptammergard]

In v7, consistent ordering of import members is enforced. The goal is to avoid arbitrary unrelated reshuffling of import members in commits due to individual IDE settings, by making the order deterministic.

// allowed in v6 and v7
import { a, b } from "..."

// allowed in v6 but disallowed in v7
import { b, a } from "..."

Also:

• JSX is now only allowed in .tsx files. No action should be required since we're not using JavaScript for writing React, but the rule can be disabled in special cases when needed.
• react/prop-types is enabled, which will cause an error when props are not typed. No action should be required since we're using TypeScript to type props. UPDATE: This rule was re-disabled in 7.0.1 due to reporting false positives and not providing additional value.
• A minimum of v8 of ESLint is required.