Bring discord badge to life (#567)

* Switch to discord badge with number of users in it

* Make matrix badge consistent with discord badge

README.md

@@ -22,9 +22,9 @@
 [i2]: https://paritytech.github.io/ink/ink_prelude
 [j1]: https://img.shields.io/badge/click-blue.svg
 [j2]: https://paritytech.github.io/ink/ink_lang
-[k1]: https://img.shields.io/badge/chat%20on-matrix-brightgreen.svg?style=flat
+[k1]: https://img.shields.io/badge/matrix-chat-brightgreen.svg?style=flat
 [k2]: https://riot.im/app/#/room/#ink:matrix.parity.io
-[l1]: https://img.shields.io/badge/chat%20on-discord-brightgreen.svg?style=flat
+[l1]: https://img.shields.io/discord/722223075629727774?style=flat-square&label=discord
 [l2]: https://discord.gg/ztCASQE
 
 > <img src="./.images/ink-squid.svg" alt="squid, the ink! mascot" style="vertical-align: middle" align="left" height="60" />ink! is an [eDSL](https://wiki.haskell.org/Embedded_domain_specific_language) to write WebAssembly based smart contracts using the Rust programming language. The compilation target are blockchains built on the [Substrate](/~https://github.com/paritytech/substrate) framework.