docs: add command to show Playwright report in README

Author: niktverd

playwright/README.md

@@ -136,3 +136,4 @@
 - `npm run playwright:docker` - run tests using docker
 - `npm run playwright:docker:update` - update screenshots using docker
 - `npm run playwright:docker:clear-cache` - clear node_modules cache for docker container and clear cache vite
+- `npx playwright show-report ./playwright-report-docker` - show report