Add Python language worker with major version 4

integrationTestsBuild/V4/HostBuild.json

@@ -10,5 +10,9 @@
   {
     "Name": "Microsoft.Azure.Functions.PowerShellWorker.PS7.2",
     "MajorVersion": "4"
+  },
+  {
+    "Name": "Microsoft.Azure.Functions.PythonWorker",
+    "MajorVersion": "4"
   }
 ]