ocamlPackages.type_conv: 112.01.01 -> 113.00.02

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 113.00.02 with grep in /nix/store/ph9bs0vwwgpm1gcypd37ia7h3iybrzlf-ocaml-type_conv-113.00.02
- directory tree listing: https://gist.github.com/e0e5582781203fe8077a8ede54af0ef6