updated docs on logger and updated dependencies for logging. (#3)

Author: dastrobu

Package.resolved

@@ -12,8 +12,8 @@ let package = Package(
             ]),
     ],
     dependencies: [
-        .package(url: "https://github.com/IBM-Swift/LoggerAPI.git", from: "1.7.0"),
-        .package(url: "https://github.com/IBM-Swift/HeliumLogger.git", from: "1.7.0")
+        .package(url: "https://github.com/IBM-Swift/LoggerAPI.git", from: "1.8.0"),
+        .package(url: "https://github.com/IBM-Swift/HeliumLogger.git", from: "1.8.0")
     ],
     targets: [
         .target(

Package.swift

@@ -533,7 +533,7 @@ To activate logging, one must configure a logger. A simple logger is e.g.
 ```swift
 import LoggerAPI
 import HeliumLogger
-Log.log = HeliumLogger(.debug)
+Log.logger = HeliumLogger(.debug)
 
 let argTree = ArgTree()
 try! argtree.parse()