smcroute: 2.3.1 -> 2.4.0

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl -h` got 0 exit code
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl --help` got 0 exit code
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl help` got 0 exit code
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl -V` and found version 2.4.0
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl -v` and found version 2.4.0
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl --version` and found version 2.4.0
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl version` and found version 2.4.0
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcroutectl --help` and found version 2.4.0
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcrouted -h` got 0 exit code
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcrouted -v` and found version 2.4.0
- ran `/nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0/bin/smcrouted -h` and found version 2.4.0
- found 2.4.0 with grep in /nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0
- found 2.4.0 in filename of file in /nix/store/7i72915zqm0xq840hj0qr6ff57syljc9-smcroute-2.4.0

cc "@fpletz"