[Bug Report] Wrong Typescript definition for theme

[macdows]

Environment

Vuetify Version: 2.0.0
Last working version: 1.5.16
Vue Version: 2.6.10
Browsers: Chrome 75.0.3770.142
OS: Linux x86_64

Steps to reproduce

Open main.ts in the codesandbox => tslint error

Expected Behavior

No linting error

Actual Behavior

Type '{ base: string; darken1: string; }' is missing the following properties from type 'VuetifyParsedThemeItem': lighten5, lighten4, lighten3, lighten2, and 4 more. ts(2345)

Reproduction Link

https://codesandbox.io/s/vue-template-hok88

Other comments

In the VuetifyParsedThemeItem definition all the lighten and darken properties are required.
It means that the following example from the official documentation does not work :

// src/plugins/vuetify/theme.js

import colors from 'vuetify/lib/util/colors'

export default {
  primary: {
    base: colors.purple.base,
    darken1: colors.purple.darken2,
  },
  secondary: colors.indigo,
  // All keys will generate theme styles,
  // Here we add a custom `tertiary` color
  tertiary: colors.pink.base,
}

Shouldn't the lighten and darken variants be optional so you can set only the ones you need ?
Like so :

export interface VuetifyParsedThemeItem {
  [name: string]: string

  base: string
  lighten5?: string
  lighten4?: string
  lighten3?: string
  lighten2?: string
  lighten1?: string
  darken1?: string
  darken2?: string
  darken3?: string
  darken4?: string
}