Adding my name to TorchToLinalg maintainership (#4708)

New to the project, but I do care a lot how we lower to Linalg, as this
is crucial to getting good performance in Lighthouse and other projects.

Happy to help in other places, too, if needed.

Author: rengolin

docs/code_owners.md

@@ -27,6 +27,7 @@ and Clang's
 
 - Ramiro Leal-Cavazos (@ramiro050) - emeritus
 - Zach Garvey (@zjgarvey)
+- Renato Golin (@rengolin)
 
 ### CI / Build system / Packaging / [Release](https://github.com/llvm/torch-mlir-release)