Bump System.IO.Abstractions.TestingHelpers from 20.0.4 to 20.0.15 (#1505)

Bumps [System.IO.Abstractions.TestingHelpers](https://github.com/TestableIO/System.IO.Abstractions) from 20.0.4 to 20.0.15.
- [Release notes](https://github.com/TestableIO/System.IO.Abstractions/releases)
- [Commits](TestableIO/System.IO.Abstractions@v20.0.4...v20.0.15)

---
updated-dependencies:
- dependency-name: System.IO.Abstractions.TestingHelpers
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

tests/KubernetesClient.Classic.Tests/KubernetesClient.Classic.Tests.csproj

@@ -10,7 +10,7 @@
       <PackageReference Include="MartinCostello.Logging.XUnit" Version="0.3.0" />
       <PackageReference Include="FluentAssertions" Version="6.12.0" />
       <PackageReference Include="Microsoft.Extensions.Logging" Version="8.0.0" />
-      <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="20.0.4" />
+      <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="20.0.15" />
       <PackageReference Include="System.Reactive" Version="6.0.0" />
       <PackageReference Include="Nito.AsyncEx" Version="5.1.2" />
       <PackageReference Include="Portable.BouncyCastle" Version="1.9.0" />

tests/KubernetesClient.Tests/KubernetesClient.Tests.csproj

@@ -9,7 +9,7 @@
       <PackageReference Include="MartinCostello.Logging.XUnit" Version="0.3.0" />
       <PackageReference Include="FluentAssertions" Version="6.12.0" />
       <PackageReference Include="Microsoft.Extensions.Logging" Version="8.0.0" />
-      <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="20.0.4" />
+      <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="20.0.15" />
       <PackageReference Include="System.Reactive" Version="6.0.0" />
       <PackageReference Include="Nito.AsyncEx" Version="5.1.2" />
       <PackageReference Include="Portable.BouncyCastle" Version="1.9.0" />