php: 7.2.5 -> 7.2.6

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

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

These checks were done:

- built on NixOS
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/phar.phar passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/phar passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/php passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/phpdbg passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/php-cgi passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/pear passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/peardev passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/pecl passed the binary check.
- /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6/bin/php-fpm passed the binary check.
- 9 of 9 passed binary check by having a zero exit code.
- 0 of 9 passed binary check by having the new version present in output.
- found 7.2.6 with grep in /nix/store/25l2hz7njpg9glpmslcadkgqwai5f77s-php-7.2.6
- directory tree listing: https://gist.github.com/409d2cfaa7e805714825281fbaba0d0f
- du listing: https://gist.github.com/7fbd8e3d56524f70b3dfb94c045fccd2