Fix dependency context test

Author: dsplaisted

src/Assets/TestPackages/dotnet-dependency-context-test/dotnet-dependency-context-test.csproj

@@ -8,7 +8,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="$(MicrosoftExtensionsDependencyModelPackageVersion)" />
+    <!-- .NET 6 versions of this package no longer support .NET Core 2.2, so hard-code the version here to 5.0 -->
+    <PackageReference Include="Microsoft.Extensions.DependencyModel" Version="5.0.0" />
   </ItemGroup>
 
 </Project>