Removed extension of ImplicitlyUnwrappedOptional

[Gruppio]

ImplicitlyUnwrappedOptional was already deprecated and it has been removed in swift 4.2 If you don't remove this extension Dip won't compile with Swift 4.2

[ilyapuchka]

@Gruppio thanks, but this will be merged only when Swift 4.2 is released

[beefon]

Is there a way to compile this conditionally?

[beefon]

https://github.com/apple/swift-evolution/blob/master/proposals/0020-if-swift-version.md

[beefon]

I assume this PR might be updated with

#if swift(<4.2)
extension ImplicitlyUnwrappedOptional: BoxType {        
   var unboxed: Any? {      
     return self ?? nil     
   }        
 }
#endif

[Gruppio]

I've add the check if swift is >= 4.1, so it is removed a warning in the current stable release ( 4.1 )