add: hole-punch nim-v1.15 peer

[rlve]

Add nim-v1.15 to hole-punch interop tests as dialer/listener.

[rlve]

Oops, was working locally 🤔

[rlve]

I made the workflow pass on my fork on a default github runner (with little changes to not use interface_name Docker Compose feature, as it's not available there): rlve#3

Which suggests that the issue might be with the connectivity of the self-hosted runner.

cc: @richard-ramos