Bump the dotnet group

Bumps the dotnet group in /docs/machine-learning/tutorials/snippets/predict-prices/csharp with 2 updates: [Microsoft.ML](https://github.com/dotnet/machinelearning) and [Microsoft.ML.FastTree](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)

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)

Updates `Microsoft.ML.FastTree` 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
- dependency-name: Microsoft.ML
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dotnet
- dependency-name: Microsoft.ML.FastTree
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dotnet
...

Signed-off-by: dependabot[bot] <support@github.com>

docs/machine-learning/tutorials/snippets/predict-prices/csharp/TaxiFarePrediction.csproj

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