chore: extend CODEOWNERS file to include platform-specific constraints files (#2559)

* Add more files to CODEOWNERS

* Uncomment cibuildwheel-maintainers for the entire constraints

* Core maintainers are all watching the repo anyway

Author: agriyakhetarpal

.github/CODEOWNERS

@@ -1,3 +1,7 @@
+# Specification files for platform maintainers
 cibuildwheel/platforms/ios.py         @freakboy3742
 cibuildwheel/platforms/pyodide.py     @hoodmane @ryanking13 @agriyakhetarpal
 cibuildwheel/platforms/android.py     @mhsmith
+
+# Constraints files
+cibuildwheel/resources/constraints-pyodide*.txt @hoodmane @ryanking13 @agriyakhetarpal