Update CODEOWNERS

Code generation for AutoML was moved from feature/automl branch to master hence updating the codeowners for code generation project.

.github/CODEOWNERS

@@ -6,6 +6,9 @@
 
 # Reviewers for files owned by AutoML team
 src/Microsoft.ML.AutoML	@dotnet/mlnet-automl
+src/Microsoft.ML.CodeGenerator	@dotnet/mlnet-automl
 test/Microsoft.ML.AutoML.Tests	@dotnet/mlnet-automl
+test/Microsoft.ML.CodeGenerator.Tests	@dotnet/mlnet-automl
 pkg/Microsoft.ML.AutoML	@dotnet/mlnet-automl
+pkg/Microsoft.ML.CodeGenerator	@dotnet/mlnet-automl
 docs/samples/Microsoft.ML.AutoML.Samples	@dotnet/mlnet-automl