Bump Gu.Roslyn.Extensions.Source from 0.16.5 to 0.16.6

Bumps [Gu.Roslyn.Extensions.Source](https://github.com/GuOrg/Gu.Roslyn.Extensions) from 0.16.5 to 0.16.6.
- [Release notes](https://github.com/GuOrg/Gu.Roslyn.Extensions/releases)
- [Changelog](https://github.com/GuOrg/Gu.Roslyn.Extensions/blob/master/RELEASE_NOTES.md)
- [Commits](https://github.com/GuOrg/Gu.Roslyn.Extensions/commits)

---
updated-dependencies:
- dependency-name: Gu.Roslyn.Extensions.Source
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Gu.Roslyn.Asserts.Analyzers/Gu.Roslyn.Asserts.Analyzers.csproj

@@ -41,7 +41,7 @@
 
   <ItemGroup>
     <PackageReference Include="Gu.Analyzers" Version="2.0.2" PrivateAssets="all" />
-    <PackageReference Include="Gu.Roslyn.Extensions.Source" Version="0.16.5" />
+    <PackageReference Include="Gu.Roslyn.Extensions.Source" Version="0.16.6" />
     <PackageReference Include="IDisposableAnalyzers" Version="4.0.1" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.1" />
     <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="17.1.46" PrivateAssets="all" />