Outdated documentation: e2e testing tools

https://developer.wordpress.org/block-editor/explanations/architecture/automated-testing/

Thus, it’s a common question: “Why does Gutenberg use Puppeteer instead of (Cypress, Selenium, Playwright, etc)?”.

We also use Playwright, so this is wrong. I don't know why the decision is made to include Playwright, so someone who does would have to rewrite this.