Tell us about your environment

• ESLint version: 6.0.1
• eslint-plugin-vue version: 5.2.3
• Node version: 12.6.0

What did you do?

export default {
  props: {
    $css: { type: Function, default: () => '' },
  }
}

What did you expect to happen?
No warning should be emitted

What actually happened?
Prop "$css" is not in camelCase.eslint(vue/prop-name-casing)