explicitly import go-multiaddr-dns in config/bootstrap_peers
explicitly import go-multiaddr-dns in config/bootstrap_peers

We need it to parse the dnsaddr addresses. While we import it elsewhere, we
should really be importing it every where we need it so that other users can
import our packages directly.

fixes #5143

License: MIT
Signed-off-by: Steven Allen <4068f0880b399410602d694b3cc711c8a8f4727e@stebalien.com>

Luzifer/go-ipfs,ianopolous/go-ipfs,chriscool/go-ipfs,chriscool/go-ipfs,Luzifer/go-ipfs,ianopolous/go-ipfs,ianopolous/go-ipfs,Luzifer/go-ipfs,chriscool/go-ipfs