[tests] Add tests to reinforce required attributes for role="heading"

Add unit tests to ensure that there are no warnings when role="heading" is used when aria-level is provided. For example, aria-label is not required.
See #1002

Author: lb-

__tests__/src/rules/role-has-required-aria-props-test.js

@@ -69,6 +69,8 @@ ruleTester.run('role-has-required-aria-props', rule, {
     { code: '<input role="checkbox" aria-checked="false" aria-labelledby="foo" tabindex="0" {...props} type="checkbox" />' },
     { code: '<input type="checkbox" role="switch" />' },
     { code: '<MyComponent role="checkbox" aria-checked="false" aria-labelledby="foo" tabindex="0" />', settings: componentsSettings },
+    { code: '<div role="heading" aria-level={2} />' },
+    { code: '<div role="heading" aria-level="3" />' },
   )).concat(basicValidityTests).map(parserOptionsMapper),
 
   invalid: parsers.all([].concat(