Added '4' tag to compliment 4.0, latest for Swift 4

library/swift

@@ -2,7 +2,7 @@ Maintainers: Haris Amin <[email protected]> (@hamin),
              Thomas Catterall <[email protected]> (@swizzlr)
 GitRepo: https://github.com/swiftdocker/docker-swift.git
 
-Tags: 4.0, latest
+Tags: 4.0, 4, latest
 GitCommit: 545b8629ffe1f9785298203cf1382711cc2ac302
 
 Tags: 3.1.0, 3.1, 3