libbitcoin-client: 3.4.0 -> 3.5.0

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 3.5.0 with grep in /nix/store/gmwvkr4gj2n0ak2ppxwmhakqsr8ihxhc-libbitcoin-client-3.5.0
- directory tree listing: https://gist.github.com/afab2c737b7764c7fb6ea2f0bc8b9ee8