stunnel: 5.44 -> 5.45

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

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

These checks were done:

- built on NixOS
- Warning: no invocation of /nix/store/7s4vc01h5glyylky8hsjfbmyxdfr44wl-stunnel-5.45/bin/stunnel3 had a zero exit code or showed the expected version
- Warning: no invocation of /nix/store/7s4vc01h5glyylky8hsjfbmyxdfr44wl-stunnel-5.45/bin/stunnel had a zero exit code or showed the expected version
- 0 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 5.45 with grep in /nix/store/7s4vc01h5glyylky8hsjfbmyxdfr44wl-stunnel-5.45
- directory tree listing: https://gist.github.com/4c607748a7a424c16abcadab39e0a7f7
- du listing: https://gist.github.com/d4b428776b9214e913cb8a97f7698d65