Bump System.Reflection.TypeExtensions in /source/dotnet

Bumps [System.Reflection.TypeExtensions](https://github.com/dotnet/corefx) from 4.4.0 to 4.7.0.
- [Release notes](https://github.com/dotnet/corefx/releases)
- [Commits](https://github.com/dotnet/corefx/commits)

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

source/dotnet/Library/AdaptiveCards.Rendering.Html/AdaptiveCards.Rendering.Html.csproj

@@ -28,7 +28,7 @@
 
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <PackageReference Include="System.Reflection.TypeExtensions">
-      <Version>4.4.0</Version>
+      <Version>4.7.0</Version>
     </PackageReference>
   </ItemGroup>