ibus-engines.libpinyin: 1.9.2 -> 1.9.3

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 1.9.3 with grep in /nix/store/z3sdj8l860r4vdb41pi3siakp98pnx8j-ibus-libpinyin-1.9.3
- directory tree listing: https://gist.github.com/bf125939ed0636cedf0daea5f6d08219