Update plugin to be compatible with Cypress 10

[Adam Murray]

Hello 👋 I'm writing on behalf of the Cypress DX team. We wanted to notify you that some changes may need to be made to this plugin to ensure that it works in Cypress 10.

For more information, here is our official plugin update guide.

[Jon M]

Thanks for the heads up @admah, thankfully everything was compatible, but we've updated our documentation to make it clearer what the differences are for Cy10 vs 9.