chore(deps): bump Polyfill from 7.7.1 to 7.8.0 (#267)

Author: dependabot[bot]

Directory.Packages.props

@@ -17,7 +17,7 @@
     <PackageVersion Include="coverlet.msbuild" Version="6.0.2" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="NetEvolve.Extensions.XUnit" Version="2.5.0" />
-    <PackageVersion Include="Polyfill" Version="7.7.1" />
+    <PackageVersion Include="Polyfill" Version="7.8.0" />
     <PackageVersion Include="xunit" Version="2.9.2" />
   </ItemGroup>