Follow the 'required' argument for nested validations

[seeppp]

Validations now follows required argument while validating nested validations.

If we add a validation step of a nested object, which is optional, the required flag would be set false.

validations.add("optionalNestedObject", required: false, B.validations)

Therefore, we are now able to have an object like this:

struct A: Codable {
    var name: String
    var optionalNestedObject: A?
}

extension A: Validatable {
    static func validations(_ validations: inout Validations) {
        validations.add("name", as: String.self, is: .ascii)
        validations.add("optionalNestedObject", required: false, A.validations)
    }
}

The validator now validates the nested object only if optionalNestedObject != nil.

If the nested object is non-optional, you can still omit the required argument.

validations.add("nestedObject", B.validations)

[Joannis]

Thanks for the PR! I'm sorry that we didn't get to review your PR yet, but it looks great.

[Joannis]

@seeppp before merging this we'll need to update the message of the main post of this PR. I gave our release bot a semver-patch, meaning that a patch version release is created once this PR is merged. This will carry over the release notes from the main issue. Therefore, the format of the main message should change to reflect the changes/fixes, rather than a description of the problem this solves.

If you need an example, check out this (closed & merged) PR by Tanner: #2400

Let me know if you need help, by mentioning me here or on Discord.

[tanner0101]

These changes are now available in 4.10.3