Update broken tests and outdated dependencies

[gerardold94]

• Dependencies cypress-testing-library and react-testing-library which were deprecated and replaced by @testing-library/cypress and @testing-library/react respectively were the reason the tests were failing. To fix the tests these libraries were updated.

• e2e tests which were using waitForRouteChange method were failing, for some reason they were reaching a timeout error. That method was replaced by the original wait on Cypress to avoid the timeout error; it might better to try to find the issue on waitForRouteChange, but that could take more time, maybe an issue should be open on gatsby.

[parmsang]

Thanks for this. Note that I reverted back to waitForRouteChange as it still appears to be working fine for me.