Bump PolyKit.Embedded from 3.0.4 to 3.0.9 (#256)

Author: dependabot[bot]

src/TestableHttpClient/TestableHttpClient.csproj

@@ -36,7 +36,7 @@
     <PackageReference Include="System.Text.Json" Version="4.6.0" />
     <PackageReference Include="Perfors.UnreachableException" Version="1.0.0" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="All" />
-    <PackageReference Include="PolyKit.Embedded" Version="3.0.4" />
+    <PackageReference Include="PolyKit.Embedded" Version="3.0.9" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net6.0'">