Debug local issues

[jrhea]

to debug discv5 and libp2p locally i have to uncomment this line in Cargo.toml:

https://github.com/prrkl/imp/blob/c1b4b17ee1d95b44c17644cb74effd843bd8ac97/Cargo.toml#L13

if i leave it uncommented all the time, then it fails to build for people that dont have the source code locally