Bump Polyfill from 6.12.0 to 6.13.0 in /src

Bumps [Polyfill](https://github.com/SimonCropp/Polyfill) from 6.12.0 to 6.13.0.
- [Commits](SimonCropp/Polyfill@6.12.0...6.13.0)

---
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

@@ -9,7 +9,7 @@
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
     <PackageVersion Include="NUnit" Version="4.2.2" />
     <PackageVersion Include="NUnit3TestAdapter" Version="4.6.0" />
-    <PackageVersion Include="Polyfill" Version="6.12.0" />
+    <PackageVersion Include="Polyfill" Version="6.13.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.136" />
     <PackageVersion Include="Verify" Version="27.0.0-beta.5" />
     <PackageVersion Include="Verify.DiffPlex" Version="3.1.0" />