all: switch out defunct set library to different one (#16873)

* keystore, ethash, eth, miner, rpc, whisperv6: tech debt with now defunct set.

* whisperv5: swap out gopkg.in/fatih/set.v0 with supported set

whisper/whisperv6/peer.go

@@ -22,11 +22,11 @@ import (
 	"sync"
 	"time"
 
+	mapset "github.com/deckarep/golang-set"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/rlp"
-	set "gopkg.in/fatih/set.v0"
 )
 
 // Peer represents a whisper protocol peer connection.
@@ -41,7 +41,7 @@ type Peer struct {
 	bloomFilter    []byte
 	fullNode       bool
 
-	known *set.Set // Messages already known by the peer to avoid wasting bandwidth
+	known mapset.Set // Messages already known by the peer to avoid wasting bandwidth
 
 	quit chan struct{}
 }
@@ -54,7 +54,7 @@ func newPeer(host *Whisper, remote *p2p.Peer, rw p2p.MsgReadWriter) *Peer {
 		ws:             rw,
 		trusted:        false,
 		powRequirement: 0.0,
-		known:          set.New(),
+		known:          mapset.NewSet(),
 		quit:           make(chan struct{}),
 		bloomFilter:    MakeFullNodeBloom(),
 		fullNode:       true,
@@ -165,7 +165,7 @@ func (peer *Peer) mark(envelope *Envelope) {
 
 // marked checks if an envelope is already known to the remote peer.
 func (peer *Peer) marked(envelope *Envelope) bool {
-	return peer.known.Has(envelope.Hash())
+	return peer.known.Contains(envelope.Hash())
 }
 
 // expire iterates over all the known envelopes in the host and removes all