chore: add discourse badge (libp2p#327)

Author: vasco-santos

README.md

@@ -4,6 +4,7 @@ libp2p-switch JavaScript implementation
 [![](https://img.shields.io/badge/made%20by-Protocol%20Labs-blue.svg?style=flat-square)](http://ipn.io)
 [![](https://img.shields.io/badge/project-IPFS-blue.svg?style=flat-square)](http://ipfs.io/)
 [![](https://img.shields.io/badge/freenode-%23ipfs-blue.svg?style=flat-square)](http://webchat.freenode.net/?channels=%23ipfs)
+[![Discourse posts](https://img.shields.io/discourse/https/discuss.libp2p.io/posts.svg)](https://discuss.libp2p.io)
 [![Travis CI](https://flat.badgen.net/travis/libp2p/js-libp2p-switch)](https://travis-ci.com/libp2p/js-libp2p-switch)
 [![codecov](https://codecov.io/gh/libp2p/js-libp2p-switch/branch/master/graph/badge.svg)](https://codecov.io/gh/libp2p/js-libp2p-switch)
 [![Dependency Status](https://david-dm.org/libp2p/js-libp2p-switch.svg?style=flat-square)](https://david-dm.org/libp2p/js-libp2p-switch)

package.json

@@ -40,11 +40,11 @@
     "npm": ">=3.0.0"
   },
   "devDependencies": {
-    "aegir": "^18.1.0",
+    "aegir": "^18.2.1",
     "chai": "^4.2.0",
     "chai-checkmark": "^1.0.1",
     "dirty-chai": "^2.0.1",
-    "libp2p-mplex": "~0.8.4",
+    "libp2p-mplex": "~0.8.5",
     "libp2p-pnet": "~0.1.0",
     "libp2p-secio": "~0.11.1",
     "libp2p-spdy": "~0.13.3",
@@ -53,22 +53,22 @@
     "libp2p-websockets": "~0.12.2",
     "peer-book": "~0.9.1",
     "portfinder": "^1.0.20",
-    "pull-length-prefixed": "^1.3.1",
+    "pull-length-prefixed": "^1.3.2",
     "pull-mplex": "~0.1.2",
     "pull-pair": "^1.1.0",
-    "sinon": "^7.2.3",
+    "sinon": "^7.3.1",
     "webrtcsupport": "^2.2.0"
   },
   "dependencies": {
     "async": "^2.6.2",
-    "bignumber.js": "^8.0.2",
+    "bignumber.js": "^8.1.1",
     "class-is": "^1.1.0",
     "debug": "^4.1.1",
     "err-code": "^1.1.2",
     "fsm-event": "^2.1.0",
     "hashlru": "^2.3.0",
     "interface-connection": "~0.3.3",
-    "libp2p-circuit": "~0.3.5",
+    "libp2p-circuit": "~0.3.6",
     "libp2p-identify": "~0.7.6",
     "moving-average": "^1.0.0",
     "multiaddr": "^6.0.6",