Feature/setup cypress for e2e testing

[barneyjeffries]

Description of the Change

This PR adds Cypress for e2e testing, configured and with 2 tests set-up:

1. block.test - the test creates a new classic post with dummy content, opens the post and checks content has been converted to blocks
2. admin.test - the test logs in and deactivates and activates the plugin

Closes #65

How to test the Change

1. Pull changes
2. Run npm install
3. Build assets: npm run build
4. Start local environment: npm run env:start
5. Open Cypress for testing: npm run cypress:open
6. Use Cypress GUI to run tests and verify they are working

Changelog Entry

Added - e2e testing with Cypress

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[barneyjeffries]

@cadic I seem to be having the same issue I had with this PR - the tests are failing. I tried bumping the WP version.

Would you mind reviewing and letting me know what you think the issue might be?

[jeffpaul]

@iamdharmesh note this is waiting your review

[jeffpaul]

@10up/open-source-practice Cypress e2e PR up for review

[iamdharmesh]

Hi @barneyjeffries,

Thanks a lot for the Great work here, the code looks good to me.

I noticed that 1 E2E test is failing. Could you please help to check and fix it?

We are good to merge this once we fix the failing e2e test.

Thanks
cc: @jeffpaul