Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/xl2tpd/versions.

These checks were done:

- built on NixOS
- /nix/store/xvvr6zvnn8q3k0021bp74yfql82yp7q1-xl2tpd-1.3.12/bin/pfc passed the binary check.
- /nix/store/xvvr6zvnn8q3k0021bp74yfql82yp7q1-xl2tpd-1.3.12/bin/xl2tpd passed the binary check.
- /nix/store/xvvr6zvnn8q3k0021bp74yfql82yp7q1-xl2tpd-1.3.12/bin/xl2tpd-control passed the binary check.
- 2 of 3 passed binary check by having a zero exit code.
- 1 of 3 passed binary check by having the new version present in output.
- found 1.3.12 with grep in /nix/store/xvvr6zvnn8q3k0021bp74yfql82yp7q1-xl2tpd-1.3.12
- directory tree listing: https://gist.github.com/9e7e06daf4d57291dbefde0aff0da546
- du listing: https://gist.github.com/0eb400f5c7f43510ed9dc63f43181d95

xl2tpd: 1.3.10.1 -> 1.3.12