Adding Mullvad VPN under Proxy and VPN Tools (#1128)

Hey guys wanted to add Mullvad VPN to the list. Its an awesome VPN service that is cheap and needs no account information to use!

README.md

@@ -825,6 +825,7 @@ Any comments, suggestions? [Let us know!](https://github.com/jaywcjlove/awesome-
 * [V2rayU](https://github.com/yanue/V2rayU) - Macos client based on v2ray. [![Open-Source Software][OSS Icon] ![Freeware][Freeware Icon]](https://github.com/yanue/V2rayU)
 * [Windscribe](https://windscribe.com) - Gives 10gb per month free on the spot and gives limited(on free) location control. Connection also takes very less time.
 * [ClashX](https://github.com/yichengchen/clashX) - A rule based proxy For Mac base on Clash. [![Open-Source Software][OSS Icon]](https://github.com/yichengchen/clashX)![Freeware][Freeware Icon]
+* [Mullvad VPN](https://mullvad.net) - Privacy focused VPN that requires no personal information for use, keeps no logs, and allows payments with Cash Bitcoin, Monero and more.
 
 ## Utilities