chore(deps): bump Polyfill from 7.18.0 to 7.20.0

Bumps [Polyfill](https://github.com/SimonCropp/Polyfill) from 7.18.0 to 7.20.0.
- [Commits](SimonCropp/Polyfill@7.18.0...7.20.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Directory.Packages.props

@@ -19,7 +19,7 @@
     <PackageVersion Include="coverlet.msbuild" Version="6.0.4" />
     <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="NetEvolve.Extensions.XUnit" Version="2.5.67" />
-    <PackageVersion Include="Polyfill" Version="7.18.0" />
+    <PackageVersion Include="Polyfill" Version="7.20.0" />
     <PackageVersion Include="xunit" Version="2.9.3" />
   </ItemGroup>