most: 5.0.0 -> 5.0.0a

Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:

- built on NixOS
- ran `/nix/store/hl99dyzq83jifdjg00d4zcdxj3j6hqxy-most-5.0.0a/bin/most -h` got 0 exit code
- ran `/nix/store/hl99dyzq83jifdjg00d4zcdxj3j6hqxy-most-5.0.0a/bin/most help` got 0 exit code
- ran `/nix/store/hl99dyzq83jifdjg00d4zcdxj3j6hqxy-most-5.0.0a/bin/most -h` and found version 5.0.0a
- found 5.0.0a with grep in /nix/store/hl99dyzq83jifdjg00d4zcdxj3j6hqxy-most-5.0.0a
- directory tree listing: https://gist.github.com/c97521034492f9bccb53c5402a867290