feat: gossipsub 1.1 (#733)

* feat: gossipsub 1.1

BREAKING CHANGE: pubsub implementation is now directly exposed and its API was updated according to the new pubsub interface in js-libp2p-interfaces repo

* chore: use gossipsub branch with src added

* fix: add pubsub handlers adapter

* chore: fix deps

* chore: update pubsub docs and examples

* chore: apply suggestions from code review

Co-authored-by: Jacob Heun <jacobheun@gmail.com>

* chore: use new floodsub

* chore: change validator doc set

Co-authored-by: Jacob Heun <jacobheun@gmail.com>

* chore: add new gossipsub src

Co-authored-by: Jacob Heun <jacobheun@gmail.com>

src/pubsub-adapter.js

@@ -0,0 +1,40 @@
+'use strict'
+
+// Pubsub adapter to keep API with handlers while not removed.
+module.exports = (PubsubRouter, libp2p, options) => {
+  class Pubsub extends PubsubRouter {
+    /**
+     * Subscribes to a given topic.
+     * @override
+     * @param {string} topic
+     * @param {function(msg: InMessage)} [handler]
+     * @returns {void}
+     */
+    subscribe (topic, handler) {
+      // Bind provided handler
+      handler && this.on(topic, handler)
+      super.subscribe(topic)
+    }
+
+    /**
+     * Unsubscribe from the given topic.
+     * @override
+     * @param {string} topic
+     * @param {function(msg: InMessage)} [handler]
+     * @returns {void}
+     */
+    unsubscribe (topic, handler) {
+      if (!handler) {
+        this.removeAllListeners(topic)
+      } else {
+        this.removeListener(topic, handler)
+      }
+
+      if (this.listenerCount(topic) === 0) {
+        super.unsubscribe(topic)
+      }
+    }
+  }
+
+  return new Pubsub(libp2p, options)
+}