Update Directory.Packages.props

Author: SimonCropp

src/Directory.Packages.props

@@ -13,7 +13,7 @@
     <PackageVersion Include="Microsoft.EntityFrameworkCore.SqlServer" Version="10.0.8" />
     <PackageVersion Include="Npgsql" Version="10.0.2" />
     <PackageVersion Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="10.0.1" />
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.5.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="18.6.0" />
     <PackageVersion Include="NUnit" Version="4.6.1" />
     <PackageVersion Include="NUnit3TestAdapter" Version="6.2.0" />
     <PackageVersion Include="coverlet.collector" Version="10.0.1" />