Downgrade to 1.0.0 Microsoft.Extensions.DependencyModel

- workaround [https://github.com/dotnet/core-setup/issues/423]().

Author: dougbu

src/Microsoft.EntityFrameworkCore.Relational.Design.Specification.Tests/project.json

@@ -25,7 +25,7 @@
     "Microsoft.EntityFrameworkCore.Design": "1.0.0-*",
     "Microsoft.EntityFrameworkCore.Relational.Design": "1.1.0-*",
     "Microsoft.EntityFrameworkCore.Relational.Specification.Tests": "1.1.0-*",
-    "Microsoft.Extensions.DependencyModel": "1.1.0-*",
+    "Microsoft.Extensions.DependencyModel": "1.0.0",
     "NETStandard.Library": "1.6.1-*"
   },
   "frameworks": {