fix: prevent direct checks against attributes

[benmonro]

this PR prevents direct checks against attributes.

examples:

expect(element.checked).toBeTruthy()
expect(getByText('foo').checked).toBeFalsy()
expect(getByText('foo').checked).toBe(true)

expect(getByText('foo').checked).toBe(false)

expect(getByText('foo').checked).toBe(null)

expect(getByText('foox').checked).toEqual(undefined)
expect(element.checked).toBe(true)

[benmonro]

🎉 This PR is included in version 1.2.1 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀