docs: fix readme.md (#342)

**Issues addressed:**
1. Dead Peer Routing, Content Routing, Peer discovery badge images. 
2. Dead/incorrect `Open an issue...` link. This now points to the js-libp2p-kad-dht issues page, instead of a dead IPFS issues page. I also felt that pointing to the local issues page rather than IPFS was more reasonable (this is what other libp2p repos tend to do). 
3. Updated contributing badge to point to new URL. 

For the peer routing, etc. badges, I've linked the images to their respective deprecated and read-only repositories - this should prevent any future 404s and is what the updated libp2p-interfaces repo does. Clicking on the images will still redirect to the updated repositories. 

Fixes #324

Author: zeim839

README.md

@@ -71,27 +71,27 @@ async function addDHT(libp2p) {
 Note that you may want to supply your own peer discovery function and datastore
 ### Peer Routing
 
-[![](https://raw.githubusercontent.com/libp2p/js-libp2p-interfaces/master/src/peer-routing/img/badge.png)](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/interfaces/src/peer-routing)
+[![](https://raw.githubusercontent.com/libp2p/interface-peer-routing/master/img/badge.png)](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/libp2p-interfaces/src/peer-routing)
 
 ### Content Routing
 
-[![](https://raw.githubusercontent.com/libp2p/js-libp2p-interfaces/master/src/content-routing/img/badge.png)](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/interfaces/src/content-routing)
+[![](https://raw.githubusercontent.com/libp2p/interface-content-routing/master/img/badge.png)](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/libp2p-interfaces/src/content-routing)
 
 ### Peer Discovery
 
-[![](https://raw.githubusercontent.com/libp2p/js-libp2p-interfaces/master/src/peer-discovery/img/badge.png)](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/interfaces/src/peer-discovery)
+[![](https://github.com/libp2p/interface-peer-discovery/blob/master/img/badge.png?raw=true)](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/libp2p-interfaces/src/peer-discovery)
 
 ## Spec
 
 js-libp2p-kad-dht follows the [libp2p/kad-dht spec](https://github.com/libp2p/specs/tree/master/kad-dht) and implements the algorithms described in the [IPFS DHT documentation](https://docs.ipfs.io/concepts/dht/).
 
 ## Contribute
 
-Feel free to join in. All welcome. Open an [issue](https://github.com/libp2p/js-libp2p-ipfs/issues)!
+Feel free to join in. All welcome. Open an [issue](https://github.com/libp2p/js-libp2p-kad-dht/issues)!
 
 This repository falls under the IPFS [Code of Conduct](https://github.com/ipfs/community/blob/master/code-of-conduct.md).
 
-[![](https://cdn.rawgit.com/jbenet/contribute-ipfs-gif/master/img/contribute.gif)](https://github.com/ipfs/community/blob/master/contributing.md)
+[![](https://cdn.rawgit.com/jbenet/contribute-ipfs-gif/master/img/contribute.gif)](https://github.com/ipfs/community/blob/master/CONTRIBUTING.md)
 
 ## License