Update SwiftLint to 0.39.2 (#295)

* Update SwiftLint to 0.39.2

* Enable a bunch of extra rules

* Fix all warnings

* Ignore this Xcode generated folder

Co-authored-by: Olivier Halligon <olivier@halligon.net>

Sources/Environment.swift

@@ -1,13 +1,13 @@
 public struct Environment {
   public let templateClass: Template.Type
   public var extensions: [Extension]
-
   public var loader: Loader?
 
-  public init(loader: Loader? = nil,
-              extensions: [Extension] = [],
-              templateClass: Template.Type = Template.self) {
-
+  public init(
+    loader: Loader? = nil,
+    extensions: [Extension] = [],
+    templateClass: Template.Type = Template.self
+  ) {
     self.templateClass = templateClass
     self.loader = loader
     self.extensions = extensions + [DefaultExtension()]
@@ -44,5 +44,4 @@ public struct Environment {
     template.environment = self
     return try template.render(context)
   }
-
 }