upgraded xunit packages.

Author: hikalkan

test/AbpCompanyName.AbpProjectName.Tests/project.json

@@ -8,12 +8,12 @@
     "AbpCompanyName.AbpProjectName.Application": "1.0.0.0-*",
     "AbpCompanyName.AbpProjectName.EntityFramework": "1.0.0.0-*",
     "dotnet-test-xunit": "2.2.0-preview2-build1029",
-    "xunit": "2.2.0-beta2-build3300",
-    "xunit.extensibility.execution": "2.2.0-beta2-build3300",
-    "xunit.runner.visualstudio": "2.2.0-beta2-build1149",
     "Shouldly": "2.8.2",
     "Effort.EF6": "1.3.0",
-    "Abp.TestBase": "1.2.1"
+    "Abp.TestBase": "1.2.1",
+    "xunit": "2.2.0-beta4-build3444",
+    "xunit.extensibility.execution": "2.2.0-beta4-build3444",
+    "xunit.runner.visualstudio": "2.2.0-beta4-build1194"
   },
 
   "frameworks": {