Bump System.Collections.Immutable from 9.0.8 to 9.0.9

---
updated-dependencies:
- dependency-name: System.Collections.Immutable
  dependency-version: 9.0.9
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

PdfJsSharp/PdfJsSharp.csproj

@@ -49,7 +49,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="System.Collections.Immutable" Version="9.0.8" />
+    <PackageReference Include="System.Collections.Immutable" Version="9.0.9" />
   </ItemGroup>
 
   <ItemGroup>