fix port (#446)

examples/WireMock.Net.StandAlone.NETCoreApp/Properties/launchSettings.json

@@ -2,7 +2,7 @@
   "profiles": {
     "WireMock.Net.StandAlone.NETCoreApp": {
       "commandName": "Project",
-      "commandLineArgs": "--Urls http://*:9091 --WireMockLogger WireMockConsoleLogger"
+      "commandLineArgs": "--Port 9091 --WireMockLogger WireMockConsoleLogger"
     }
   }
 }

src/WireMock.Net/Owin/HostUrlOptions.cs

@@ -7,6 +7,8 @@ namespace WireMock.Owin
     {
         public ICollection<string> Urls { get; set; }
 
+        public int? Port { get; set; }
+
         public bool UseSSL { get; set; }
 
         public ICollection<(string Url, int Port)> GetDetails()
@@ -14,7 +16,7 @@ namespace WireMock.Owin
             var list = new List<(string Url, int Port)>();
             if (Urls == null)
             {
-                int port = FindFreeTcpPort();
+                int port = Port ?? FindFreeTcpPort();
                 list.Add(($"{(UseSSL ? "https" : "http")}://localhost:{port}", port));
             }
             else

src/WireMock.Net/Server/WireMockServer.cs

@@ -214,7 +214,8 @@ namespace WireMock.Server
             {
                 urlOptions = new HostUrlOptions
                 {
-                    UseSSL = settings.UseSSL == true
+                    UseSSL = settings.UseSSL == true,
+                    Port = settings.Port
                 };
             }