"addConstraint" is obsolete

[Gargo]

According to documentation:

When developing for iOS 8.0 or later, set the constraint’s [isActive](doc://com.apple.documentation/documentation/uikit/nslayoutconstraint/1527000-isactive?language=swift) property to [true](https://developer.apple.com/documentation/swift/true) instead of calling the addConstraint(_:) method directly. The isActive property automatically adds and removes the constraint from the correct view.