Update dependency System.Collections.Immutable to 6.0.1

Author: renovate[bot]

Directory.Packages.props

@@ -33,7 +33,7 @@
     <PackageVersion Include="Microsoft.Win32.Registry" Version="5.0.0" />
     <PackageVersion Include="Microsoft.Windows.CsWin32" Version="0.3.106" />
     <PackageVersion Include="Nullable" Version="1.3.1" />
-    <PackageVersion Include="System.Collections.Immutable" Version="6.0.0" />
+    <PackageVersion Include="System.Collections.Immutable" Version="6.0.1" />
     <PackageVersion Include="System.Memory" Version="4.5.5" />
     <PackageVersion Include="System.Runtime.CompilerServices.Unsafe" Version="6.0.0" />
     <PackageVersion Include="System.Threading.Tasks.Extensions" Version="4.5.4" />