Bump System.IO.Abstractions from 21.1.7 to 21.2.1

Bumps [System.IO.Abstractions](https://github.com/TestableIO/System.IO.Abstractions) from 21.1.7 to 21.2.1.
- [Release notes](https://github.com/TestableIO/System.IO.Abstractions/releases)
- [Commits](TestableIO/System.IO.Abstractions@v21.1.7...v21.2.1)

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

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

src/LibYear.Core/LibYear.Core.csproj

@@ -20,7 +20,7 @@
 	<ItemGroup>
 		<PackageReference Include="Microsoft.SourceLink.GitHub" Version="8.0.0" PrivateAssets="all" />
 		<PackageReference Include="NuGet.Protocol" Version="6.12.1" />
-		<PackageReference Include="System.IO.Abstractions" Version="21.1.7" />
+		<PackageReference Include="System.IO.Abstractions" Version="21.2.1" />
 		<None Include="../../README.md" CopyToOutputDirectory="PreserveNewest" Pack="true" PackagePath="." />
 	</ItemGroup>
 </Project>

test/LibYear.Core.Tests/LibYear.Core.Tests.csproj

@@ -9,7 +9,7 @@
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
 		<PackageReference Include="NSubstitute" Version="5.3.0" />
 		<PackageReference Include="NuGet.Protocol" Version="6.12.1" />
-		<PackageReference Include="System.IO.Abstractions" Version="21.1.7" />
+		<PackageReference Include="System.IO.Abstractions" Version="21.2.1" />
 		<PackageReference Include="xunit" Version="2.9.2" />
 		<PackageReference Include="xunit.runner.visualstudio" Version="3.0.0" />
 		<ProjectReference Include="../../src/LibYear.Core/LibYear.Core.csproj" />