Bump Microsoft.ML

Bumps the dotnet group in /docs/machine-learning/tutorials/snippets/iris-clustering/csharp with 1 update: [Microsoft.ML](https://github.com/dotnet/machinelearning).


Updates `Microsoft.ML` from 3.0.1 to 4.0.0
- [Release notes](https://github.com/dotnet/machinelearning/releases)
- [Commits](https://github.com/dotnet/machinelearning/commits)

---
updated-dependencies:
- dependency-name: Microsoft.ML
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dotnet
...

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

docs/machine-learning/tutorials/snippets/iris-clustering/csharp/IrisFlowerClustering.csproj

@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.ML" Version="3.0.1" />
+    <PackageReference Include="Microsoft.ML" Version="4.0.0" />
   </ItemGroup>
 
   <ItemGroup>