Bump System.Collections.Immutable and System.Reflection.Metadata

Bumps [System.Collections.Immutable](https://github.com/dotnet/runtime) and [System.Reflection.Metadata](https://github.com/dotnet/runtime). These dependencies needed to be updated together.

Updates `System.Collections.Immutable` from 1.5.0 to 9.0.1
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](https://github.com/dotnet/runtime/commits/v9.0.1)

Updates `System.Reflection.Metadata` from 9.0.0 to 9.0.1
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](dotnet/runtime@v9.0.0...v9.0.1)

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

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

Author: dependabot[bot]

Tests/Benchmarks/Benchmarks.csproj

@@ -12,6 +12,6 @@
     <PackageReference Include="BenchmarkDotNet" Version="0.14.0" />
     <PackageReference Include="Bogus" Version="35.6.1" />
     <!-- Resolve MSB3277 -->
-    <PackageReference Include="System.Reflection.Metadata" Version="9.0.0" Condition="'$(TargetFramework)' == 'net472'" />
+    <PackageReference Include="System.Reflection.Metadata" Version="9.0.1" Condition="'$(TargetFramework)' == 'net472'" />
   </ItemGroup>
 </Project>

Tests/FluentAssertions.Equivalency.Specs/FluentAssertions.Equivalency.Specs.csproj

@@ -17,7 +17,7 @@
       FluentAssertions.Specs.csproj for net47 does not generate a binding redirect from 4.0.4.0 to 4.0.4.1
       Upgrading to 1.6.0 gives "Could not load file or assembly 'System.Runtime.CompilerServices.Unsafe, Version=4.0.4.0"
     -->
-    <PackageReference Include="System.Collections.Immutable" Version="[1.5.0]" />
+    <PackageReference Include="System.Collections.Immutable" Version="[9.0.1]" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net6.0' OR '$(TargetFramework)' == 'net8.0'">

Tests/FluentAssertions.Specs/FluentAssertions.Specs.csproj

@@ -17,7 +17,7 @@
       FluentAssertions.Specs.csproj for net47 does not generate a binding redirect from 4.0.4.0 to 4.0.4.1
       Upgrading to 1.6.0 gives "Could not load file or assembly 'System.Runtime.CompilerServices.Unsafe, Version=4.0.4.0"
     -->
-    <PackageReference Include="System.Collections.Immutable" Version="[1.5.0]" />
+    <PackageReference Include="System.Collections.Immutable" Version="[9.0.1]" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net6.0' OR '$(TargetFramework)' == 'net8.0'">