Setup and use GitHub actions to check Symfony version compatibility #64
Description
Off the back of #60
Don't expect this library to be working with the beta of an unreleased version, but might be one to run in CI, e.g. setup a monthly travis cron with the latest tagged release of symfony, see a failure, get a pre-release ready, release it when the latest version is cut?
Creating an issue here so that this isn't forgotten (happy to do it soon), would be nice to have failures ready to go when there's a change in a pre-release version. Plus has the benefit of making code reviews a bit easier since there'll be feedback PR time too again.