feat: Fallback values

[miroslavstastny]

Add support for fallback values.
Fixes #27.

Any CSS property accepts an array of values which are all added to the styles.
Every browser will use the latest valid value (which might be a different one in different browsers, based on supported CSS in that browser):

import { makeStyles } from '@griffel/react';

const useClasses = makeStyles({
  root: {
    overflowY: ['scroll', 'overlay'],
  },
});

Produces following CSS:

.f1qdoogn{
  overflow-y: scroll;  /* Fallback for browsers which do not support overflow: overlay */
  overflow-y: overlay; /* Used by browsers which support overflow: overlay */
}

[miroslavstastny]

radius shorthand used just GriffelStylesCSSValue not allowing initial and similar values. Not sure there was any reason for that, I think this type is more correct.

[miroslavstastny]

The same applies to margin and padding

[miroslavstastny]

Ironically, csstype typings currently do not accept overlay as a valid value for overflow 😢

[layershifter]

Yup, frenic/csstype#62