Fix go.mod dependency

[AminRezaei0x443]

Dependency multiformats/go-multiaddr-net v0.2.0 is deprecated and it has no particular use in this project, thus safely can be removed. This dependency causes error on go get and prevents package installation. This PR removes the dependency and thus fixes the proposed issue.
A version bump to v0.2.1 would be ok after the merge.

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Merged in #251