Migrate PetStore to Swift 4.2

The last version was Swift 3.0 which is very old. The project had some
compile errors and was not working at all with Xcode 10.
Some changes are generated by Cocoapods using the latest version.
Manual fixes are done only for the .swift files

Author: plam4u

samples/client/petstore/swift4/default/PetstoreClient/Classes/Swaggers/APIs/FakeClassnameTags123API.swift

@@ -45,8 +45,7 @@ open class FakeClassnameTags123API {
         let parameters = JSONEncodingHelper.encodingParameters(forEncodableObject: body)
 
         var url = URLComponents(string: URLString)
-        url?.queryItems = APIHelper.mapValuesToQueryItems([
-        ])
+        url?.queryItems = APIHelper.mapValuesToQueryItems([:])
 
         let requestBuilder: RequestBuilder<Client>.Type = PetstoreClientAPI.requestBuilderFactory.getBuilder()
 

samples/client/petstore/swift4/default/SwaggerClientTests/Podfile

@@ -12,7 +12,7 @@ end
 post_install do |installer|
     installer.pods_project.targets.each do |target|
         target.build_configurations.each do |configuration|
-            configuration.build_settings['SWIFT_VERSION'] = "3.0"
+            configuration.build_settings['SWIFT_VERSION'] = "4.2"
         end
     end
 end

samples/client/petstore/swift4/default/SwaggerClientTests/Podfile.lock

@@ -6,14 +6,18 @@ PODS:
 DEPENDENCIES:
   - PetstoreClient (from `../`)
 
+SPEC REPOS:
+  https://github.com/cocoapods/specs.git:
+    - Alamofire
+
 EXTERNAL SOURCES:
   PetstoreClient:
-    :path: ../
+    :path: "../"
 
 SPEC CHECKSUMS:
   Alamofire: f28cdffd29de33a7bfa022cbd63ae95a27fae140
-  PetstoreClient: fef7934ac90bd28c2b81cc5234615112f9ace5f5
+  PetstoreClient: 9f1c86c3f7194758e922fb64277bfb4fc60bbf20
 
-PODFILE CHECKSUM: 417049e9ed0e4680602b34d838294778389bd418
+PODFILE CHECKSUM: 065fc3a3ec186d4f60ef8c7d9624786f07955f2f
 
-COCOAPODS: 1.4.0
+COCOAPODS: 1.7.1