chore(deps): update dependency system.collections.immutable to v9

Author: renovate[bot]

src/Directory.Packages.props

@@ -40,7 +40,7 @@
     <PackageVersion Include="Splat.DryIoc" Version="$(SplatVersion)" />
     <PackageVersion Include="Splat.Ninject" Version="$(SplatVersion)" />
     <PackageVersion Include="stylecop.analyzers" Version="1.2.0-beta.556" />
-    <PackageVersion Include="System.Collections.Immutable" Version="8.0.0" />
+    <PackageVersion Include="System.Collections.Immutable" Version="9.0.9" />
     <PackageVersion Include="System.IO.FileSystem.Primitives" Version="4.3.0" />
     <PackageVersion Include="System.Runtime.Serialization.Primitives" Version="4.3.0" />
     <PackageVersion Include="System.Text.Json" Version="9.0.8" />