CODEOWNERS: extend scope of MLIR transform dialect

There are a bunch of related directories in another dialects.

Author: ftynse

.github/CODEOWNERS

@@ -96,6 +96,7 @@ clang/test/AST/Interp/ @tbaederr
 # Transform Dialect in MLIR.
 /mlir/include/mlir/Dialect/Transform/* @ftynse @nicolasvasilache
 /mlir/lib/Dialect/Transform/* @ftynse @nicolasvasilache
+/mlir/**/*TransformOps* @ftynse @nicolasvasilache
 
 # SPIR-V Dialect in MLIR.
 /mlir/**/SPIRV/ @antiagainst @kuhar