Update dependency System.IO.Abstractions to v12.1.1 (#58)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

System.IO.Abstractions.Analyzers.Tests/System.IO.Abstractions.Analyzers.Tests.csproj

@@ -8,7 +8,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.6.1" />
-		<PackageReference Include="System.IO.Abstractions" Version="12.0.9" />
+		<PackageReference Include="System.IO.Abstractions" Version="12.1.1" />
 		<PackageReference Include="xunit" Version="2.4.1" />
 		<PackageReference Include="xunit.runner.visualstudio" Version="2.4.2" />
 	</ItemGroup>