* run go mod tidy
* omit receiver name if unused
* remove unused type testkey in tests
* fix duplicate import of go-multiaddr
* fix use of deprecated peer.IDB58{Encode,Decode}
* use bytes.Equal instead of bytes.Compare
* fix unnecessary assigments to blank identifier
* use time.Until instead of t.Sub(time.Now())
* fix use of deprecated go-multihash.ID
* add missing error check in envelope test
* fix error check in tests
