[META] Mark Upgrade Status 8 as beta

#3059316: Tests fail due to undefined index in git_deploy is now resolved in git deploy. Thanks @kfritsche. Now we are experiencing #3050653: is_dir() expects parameter 1 to be a valid path, bool given on testbot.

https://www.drupal.org/project/upgrade_status/releases/8.x-1.0-alpha4 is now out, thanks @kfritsche and @mglaman for a lot of work this week! We are getting quite close. Both big bug reports are now back with their reporters to try to reproduce with the latest version. Removing the issues we resolved or not actionable now.

Solved docs issue. The two critical bugs are still standing unfortunately.

With the latest release, #3058022: Upgrade Status gets into endless scanning process has been eliminated down to a specific issue with Redirect vs phpstan at #3065760: Fail more gracefully when exceptions happen, eg. Uncaught PHPStan\Broker\ClassAutoloadingException with Redirect 8.x-1.3, so not a systemic issue.

The only remaining one is #3053781: Scanning queue items are not valid which surely is not reproducible as-is anymore as the latest release does not have a queue at all. That said, I would love to see if if we can eliminate that in favor of some specific issue or uncover any systemic issues in case there are any.

#3053781: Scanning queue items are not valid was not getting feedback about the original issue in 6 weeks now and there is not even a queue anymore in the module, so that should not be a problem. Therefore I decided to go ahead and close that and make the beta happen.

https://twitter.com/gaborhojtsy/status/1148977097370689536 for RT :)