v4 Release

[whymarrh]

This issue tracks the progress of the v4 release.

Changes:

• Update to ESLint 7 (Update to ESLint 7 #46)
• Disable space-before-function-paren (Disable space-before-function-paren #39)
• Further restrict unused expressions (Further restrict unused expressions #66)

The draft version bump: #64

[whymarrh]

cc @MetaMask/devs is there anything else we want to put into this release?

[brad-decker]

@whymarrh I think that this one isn't too controversial, referencing from MetaMask/metamask-extension#8595

    // 'lines-around-comment': 'error',
    // Our eslint config has the default setting for this as error. This
    // include beforeBlockComment: true, but in order to match the prettier
    // spec you have to enable before and after blocks, objects and arrays
    // https://github.com/prettier/eslint-config-prettier#lines-around-comment
    'lines-around-comment': [
      'error',
      {
        beforeBlockComment: true,
        afterLineComment: false,
        allowBlockStart: true,
        allowBlockEnd: true,
        allowObjectStart: true,
        allowObjectEnd: true,
        allowArrayStart: true,
        allowArrayEnd: true,
      },
    ],

It mostly conforms to what we currently have set but with some additional allowances for comments at the start and end of certain object types. This moves us towards an eslint configuration that doesn't conflict with prettier.

[Gudahtt]

This has been released: https://github.com/MetaMask/eslint-config/releases/tag/v4.0.0