fix: add ping service where dht is used

[achingbrain]

The next major release of the @libp2p/kad-dht module introduces a dependency on @libp2p/ping so make sure it's in the config.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works