Bump Polyfill from 6.8.0 to 6.9.0 in /src

Bumps [Polyfill](https://github.com/SimonCropp/Polyfill) from 6.8.0 to 6.9.0.
- [Commits](SimonCropp/Polyfill@6.8.0...6.9.0)

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

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src/Directory.Packages.props

@@ -8,7 +8,7 @@
     <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="6.8.0" />
+    <PackageVersion Include="Polyfill" Version="6.9.0" />
     <PackageVersion Include="ProjectDefaults" Version="1.0.135" />
     <PackageVersion Include="System.Drawing.Common" Version="8.0.8" />
     <PackageVersion Include="Verify" Version="26.4.5" />