Removed option deep in Validator/Valid is still present

[janedbal]

Valid constraint has deprecated option deep since 2.5 and it was removed in 3.0. The deprecation isn't mentioned in previous versions of docs and the removed option are still documented in 3.0

[xabbuh]

That's good catch @janedbal! Thank you very much for reporting this. What we actually need to do is to mark the option as deprecated in the 2.7 branch (older branches are not maintained anymore except for 2.3 which is not affected by this) and after that entirely remove the option from the 3.0 branch.