Warning if swapcli and swapd are on different versions
Do we want some kind of warning when `swapcli` and `swapd` not the same version?
```text
$ ./bin/swapcli version
swapcli: v0.4.0-go1.20.5
swapd: dev-7619b9a-dirty-go1.20.5
p2p version: /atomic-swap/mainnet/2
env: mainnet
swap creator address: 0x377ed3a60007048DF00135637521170628De89E5
```
I think that's what other programs do. If someone has a suggestion on what the warning should look like, please add a comment here.

I'd probably just add a line at the end like this:
```text
$ ./bin/swapcli version
swapcli: v0.4.0-go1.20.5
swapd: dev-7619b9a-dirty-go1.20.5
p2p version: /atomic-swap/mainnet/2
env: mainnet
swap creator address: 0x377ed3a60007048DF00135637521170628De89E5

WARNING: client and server versions are different
```