Integrate typescript-eslint v2 as soon as becomes stable

[IlCallo]

typescript-eslint/typescript-eslint#501 (comment)

typescript-eslint v2 will be released as stable in a couple of weeks and contains some fixes for problems we noticed while moving away from TSLint

It must be updated after the release

[IlCallo]

Part of the update should be check new rules defaults (with or without Prettier)

[IlCallo]

V2 has been released.
There are some problems with Vue template linting, when it comes to JS/TS related directives, which I'm going to link here.

vuejs/vue-eslint-parser#55
vuejs/eslint-plugin-vue#944
typescript-eslint/typescript-eslint#883

Problems root cause is still under investigation.

[IlCallo]

Steps to execute the upgrade.

.eslintrc.js
'plugin:@typescript-eslint/recommended-requiring-type-checking' should be added right after 'plugin:@typescript-eslint/recommended', into extends array.

extraFileExtensions: ['.vue'] should be added into parserOptions

Comments about typescript-eslint v2 release into rules property can be removed, as well as the @typescript-eslint/indent rule (style rules have been removed from recommended config).

package.json
@typescript-eslint/eslint-plugin and "@typescript-eslint/parser should be updated to latest release

Fix linting problems
async usage where not needed
async keywork should be removed from all boot files default exports, because it isn't actually used (there is no await inside any of those AFAIK)

Vuex boilerplate
no-empty-function complains about actions, getters and mutations files because they have an empty function body.
Adding a simple comment like // your code will solve this.
Unusued params will error too, I wrapped those into a multiline comment.

export function someAction(/* context */) {
  // your code
}

[IlCallo]

Update: typescript-eslint/typescript-eslint#890
Someone is hopefully taking care of the problem

[IlCallo]

There are some problems with Vue template linting

Problems have been solved (typescript-eslint/typescript-eslint#1083) since v2.5.0

[IlCallo]

Fixed by #48