Support TypeScript v4.x

Versions:

• prettier-eslint version: 11.0.0

Problem description:

TypeScript has recently released a new update which bumped the major. Unfortunately, TypeScript doesn’t adhere to semver (see microsoft/TypeScript#14116). This unfortunately means that if a user’s project depends on TypeScript v4.0, npm/yarn will install a separate TypeScript v3.9 just for this package in order to fulfill the dependency version ranges.

Suggested solution:

Using >=3.9.2 as the dependency version for the typescript package should fix this issue while keeping keeping the option to use older, still compatible TypeScript versions. See https://docs.npmjs.com/files/package.json#dependencies.

Relevant: #391

[zimme]

As for this specific issue. I do believe we walt to changed all the typescript/vue/other parsers to optional dependencies and check if thery’re available and only use them in those cases.

As well as loosening the version ranges on those dependencies.

[zimme]

I don’t really use this library any longer as I don’t need my prettier setting being inferred from my eslint settings, which is what this library provides over just using prettier && eslint --fix. So there is still a “need” for this package but the recommended way of using prettier with eslint is to actually use eslint-config-prettier which disables all eslint rules that conflict with prettier.