Bump NuGet.Packaging and Microsoft.NETFramework.ReferenceAssemblies

Bumps [NuGet.Packaging](https://github.com/NuGet/NuGet.Client) and [Microsoft.NETFramework.ReferenceAssemblies](https://github.com/Microsoft/dotnet). These dependencies needed to be updated together.

Updates `NuGet.Packaging` from 6.10.1 to 6.12.1
- [Release notes](https://github.com/NuGet/NuGet.Client/releases)
- [Commits](https://github.com/NuGet/NuGet.Client/commits)

Updates `Microsoft.NETFramework.ReferenceAssemblies` from 1.0.3 to 1.0.3
- [Commits](https://github.com/Microsoft/dotnet/commits)

---
updated-dependencies:
- dependency-name: NuGet.Packaging
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: Microsoft.NETFramework.ReferenceAssemblies
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

src/NuGetizer.Tasks/NuGetizer.Tasks.csproj

@@ -20,7 +20,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Build.Tasks.Core" Version="15.9.20" PrivateAssets="all" />
-    <PackageReference Include="NuGet.Packaging" Version="6.10.1" PrivateAssets="all" />
+    <PackageReference Include="NuGet.Packaging" Version="6.12.1" PrivateAssets="all" />
     <PackageReference Include="NuGet.ProjectManagement" Version="4.2.0" PrivateAssets="all" />
     <PackageReference Include="PolySharp" Version="1.14.1" PrivateAssets="all" />
     <PackageReference Include="ThisAssembly.Project" Version="1.5.0" PrivateAssets="all" />

src/NuGetizer.Tests/NuGetizer.Tests.csproj

@@ -18,7 +18,7 @@
     <PackageReference Include="MSBuild.StructuredLogger" Version="2.2.386" />
     <PackageReference Include="System.IO.Compression" Version="4.3.0" />
     <PackageReference Include="System.IO.Compression.ZipFile" Version="4.3.0" />
-    <PackageReference Include="NuGet.Packaging" Version="6.10.1" />
+    <PackageReference Include="NuGet.Packaging" Version="6.12.1" />
     <PackageReference Include="NuGet.ProjectManagement" Version="4.2.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageReference Include="Microsoft.TestPlatform.ObjectModel" Version="17.10.0" />