We have been using Yarn as a package manager for some time, but since a while, PNPM has demonstrated to be a better alternative in terms of speed, disk space efficiency, dependency isolation and security.

This pull request migrates the package manager of the repo from Yarn to PNPM to get the advantages that it brings.

Note: as part of this pull request, the id of the Docker Cache was using the old .playwright_docker_version file that doesn't exist anymore in the repository. Now the version of the Playwright Docker image is taken also from the package.json using a bash script.