feature request - allow runOnly tags to fall through or use array values

Hi,

Some background. Let's say I have a div with a color green and a background color of green. Running this test correctly fails the contrast check:

const a11yOptions: RunOptions = {
      runOnly: {
        type: 'tag',
        values: ['wcag2aa']
      }
    };
cy.checkA11y(null, a11yOptions as Options);

But if I set values: ['wcag2aaa] it fails using

"axe-core": "^4.3.5",
"cypress": "^9.2.0",
"cypress-axe": "^0.13.0",

It also fails with wcag21aa, even though 2.1 extends 2.0. I would expect that using the tag 2.1aaa would check everything in 2.1aaa, 2.1aa, 2.1a, 2.1, 2.0aaa, 2.0aa, 2.0a, 2.0, 1aaa, 1aa, 1a, and 1.

The example for getRules shows that rules have multiple tags, so this may be a problem/issue for the axe.run team at Deque instead. If they don't have the rules tagged with all of the appropriate fall through values, then checking for a level won't get all of the lower levels.

thanks!

Start by tracing how cypress-axe forwards the runOnly option to axe.run, then compare the reported behavior with axe-core's getRules output and tag definitions. Determine whether tag fall-through or array values can be supported here or belongs in axe-core; done means the expected WCAG inheritance behavior is implemented or the upstream limitation is documented.