fix: peerRouting.findPeer() trying to find self

[zeim839]

Resolves an issue where nodes running findPeer() on themselves return abstract aggregateErrors instead of something "more suitable" like ERR_DIALED_SELF. Original issue can be found here.

This is accomplished by comparing the _idB58String of the ID parameter to this._peerId._idB58String at peer-routing.js. if the two values are equal, an error is thrown alerting the user of the mistake. For example:

async findPeer (id, options) { // eslint-disable-line require-await
    ...

    if (id._idB58String == this._peerId._idB58String) throw errCode(new Error('Cannot search for self'), 'ERR_DIALED_SELF')
    
   ...
}

[vasco-santos]

Thanks @zeim839

Can you please add a test in https://github.com/libp2p/js-libp2p/blob/master/test/peer-routing/peer-routing.node.js#L53 and https://github.com/libp2p/js-libp2p/blob/master/test/peer-routing/peer-routing.node.js#L274 with a fail expect such as in https://github.com/libp2p/js-libp2p/blob/master/test/peer-routing/peer-routing.node.js#L37 ?

[zeim839]

@vasco-santos Added the requested tests to the best of my knowledge. They both pass. Let me know if there's anything else I need to change/improve.

[vasco-santos]

LGTM (pushed commit fixing linting)

Thanks @zeim839