Bump Polyfill from 6.3.0 to 6.4.0 in /src

Bumps [Polyfill](https://github.com/SimonCropp/Polyfill) from 6.3.0 to 6.4.0.
- [Commits](SimonCropp/Polyfill@6.3.0...6.4.0)

---
updated-dependencies:
- dependency-name: Polyfill
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/Directory.Packages.props

@@ -10,7 +10,7 @@
     <PackageVersion Include="Microsoft.Build.Tasks.Core" Version="17.11.4" />
     <PackageVersion Include="Microsoft.Data.SqlClient" Version="5.2.1" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
-    <PackageVersion Include="Polyfill" Version="6.3.0" />
+    <PackageVersion Include="Polyfill" Version="6.4.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.134" />
     <PackageVersion Include="Serilog.AspNetCore" Version="8.0.2" />
     <PackageVersion Include="System.Reflection.Metadata" Version="8.0.0" />