chore: remove outdated info in README and link to libp2p-implementers…

… slack (#2405)

README.md

@@ -59,14 +59,14 @@ Examples can be found in the [examples folder](examples).
 
 # Contribute
 
-go-libp2p is part of [The IPFS Project](https://github.com/ipfs/ipfs), and is MIT-licensed open source software. We welcome contributions big and small! Take a look at the [community contributing notes](https://github.com/ipfs/community/blob/master/CONTRIBUTING.md). Please make sure to check the [issues](https://github.com/ipfs/go-libp2p/issues). Search the closed ones before reporting things, and help us with the open ones.
+go-libp2p is MIT-licensed open source software. We welcome contributions big and small! Take a look at the [community contributing notes](https://github.com/ipfs/community/blob/master/CONTRIBUTING.md). Please make sure to check the [issues](https://github.com/libp2p/go-libp2p/issues). Search the closed ones before reporting things, and help us with the open ones.
 
 Guidelines:
 
 - read the [libp2p spec](https://github.com/libp2p/specs)
-- ask questions or talk about things in  our [discussion forums](https://discuss.libp2p.io), or open an [issue](https://github.com/libp2p/go-libp2p/issues) for bug reports, or #libp2p on freenode.
+- ask questions or talk about things in our [discussion forums](https://discuss.libp2p.io), or open an [issue](https://github.com/libp2p/go-libp2p/issues) for bug reports, or #libp2p-implementers on [Filecoin slack](https://filecoin.io/slack).
 - ensure you are able to contribute (no legal issues please -- we use the DCO)
-- get in touch with @marten-seemann about how best to contribute
+- get in touch with @libp2p/go-libp2p-maintainers about how best to contribute
 - have fun!
 
 There's a few things you can do right now to help out: