Deprecations break rector

[bobvandevijver]

Bug Report

Having a deprecated rule configured results in a failure (exit code 1), instead of the documented "it only prints a message".

Subject	Details
Rector version	2.6.3

 [ERROR] Could not process                                                      
         "/builds/8bAKuozDA/0/idb/idb/src/Idb/AdminGeneratorBundle/Form/Type/Adm
         inLottery/Options.php" file, due to:                                   
         "System error:                                                         
         ""Rector\Transform\Rector\Class_\AddInterfaceByTraitRector" rule is    
         deprecated, as too niche; use a custom rule scoped to your own trait   
         and interface pair instead"                                            
         Run Rector with "--debug" option and post the report here: https://github.com/rectorphp/rector/issues/new". On line:
         47
 [WARNING] Registered rule "Rector\Transform\Rector\Class_\AddInterfaceByTraitRector" is deprecated and will be removed.
           Upgrade your config to use another rule or remove it

Minimal PHP Code Causing Issue

Use the AddInterfaceByTraitRector rector.

Expected Behaviour

Rector should not end with exit code 1.

[TomasVotruba]

Fixed in rectorphp/rector-src#8358