Description
On a big work project (that started with Symfony 2.1 and is now on 4.3) we recently introduced the PHPUnitBridge to keep track of deprecations.

Unfortunately it currently reports a variety (> 2000) of deprecations trigged in our own code-base. We are slowly fixing those but this will take some time.

While we are still fixing those deprecations unfortunately whenever new code is merged it might introduce more/new deprecations again 😢

I was thinking it would be really nice to be able to make our CI build fail only for new deprecations reported by the bridge.

This is similar to the phpstan baseline feature maybe: https://medium.com/@ondrejmirtes/phpstans-baseline-feature-lets-you-hold-new-code-to-a-higher-standard-e77d815a5dff

WDYT? Is this something that might be interesting and not too complex to implement?