fix(package): update libp2p-floodsub to version 0.20.0

Closes #2603

Author: greenkeeper[bot]

Diff for: package.json

@@ -135,7 +135,7 @@
     "libp2p-crypto": "^0.16.2",
     "libp2p-delegated-content-routing": "^0.3.1",
     "libp2p-delegated-peer-routing": "^0.3.1",
-    "libp2p-floodsub": "^0.18.0",
+    "libp2p-floodsub": "^0.20.0",
     "libp2p-gossipsub": "~0.0.5",
     "libp2p-kad-dht": "~0.16.0",
     "libp2p-keychain": "^0.5.1",