Allow alternate cases in Vue's v-bind statements for CSS/SCSS in .vue files

[yokuze]

Vue supports: https://vuejs.org/api/sfc-css-features.html#v-bind-in-css , which reactively binds refs from the setup function to a CSS property value.

The refs are named according to our TypeScript const/let naming standards, so they conflict with the value-keyword-case Stylelint rule that enforces lowercase CSS values.

We can allow other cases inside of v-bind only, like this:

value-keyword-case:
   - lower
   - ignoreFunctions:
      - v-bind