opendht: 1.3.4 -> 1.5.0

Semi-automatic update. These checks were performed:

- built on NixOS
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtnode -h` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtnode --help` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtchat -h` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtchat --help` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtscanner -h` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtscanner --help` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtscanner help` got 0 exit code
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtscanner -V` and found version 1.5.0
- ran `/nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0/bin/dhtscanner --version` and found version 1.5.0
- found 1.5.0 with grep in /nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0
- found 1.5.0 in filename of file in /nix/store/204499k26yrbhl1mq7spslsc5fvmb81b-opendht-1.5.0

cc "@taeer @olynch"