Bump Polyfill from 7.7.1 to 7.8.0 in /src (#583)

Author: dependabot[bot]

src/Directory.Packages.props

@@ -10,7 +10,7 @@
     <PackageVersion Include="Fody" Version="6.9.1" />
     <PackageVersion Include="MarkdownSnippets.MsBuild" Version="27.0.2" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageVersion Include="Polyfill" Version="7.7.1" />
+    <PackageVersion Include="Polyfill" Version="7.8.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.147" />
     <PackageVersion Include="Resourcer.Fody" Version="1.8.1" />
     <PackageVersion Include="Serilog" Version="4.2.0" />