xmlsec: 1.2.25 -> 1.2.26 (#41655)

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

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

These checks were done:

- built on NixOS
- /nix/store/y5z1vxy9v75bpsjl4z3xg1l4m0d8iqg1-xmlsec-1.2.26/bin/.xmlsec1-wrapped passed the binary check.
- /nix/store/y5z1vxy9v75bpsjl4z3xg1l4m0d8iqg1-xmlsec-1.2.26/bin/xmlsec1 passed the binary check.
- 2 of 2 passed binary check by having a zero exit code.
- 0 of 2 passed binary check by having the new version present in output.
- found 1.2.26 with grep in /nix/store/y5z1vxy9v75bpsjl4z3xg1l4m0d8iqg1-xmlsec-1.2.26
- directory tree listing: https://gist.github.com/35b63e4ccf9a1df1b167177e91716a4e
- du listing: https://gist.github.com/d45eba60006ba229e2682ff2db682d96