README.md: add gitlab-ci badge

README.md

@@ -1,6 +1,6 @@
 # SoftEther VPN
 
-[![AppVeyor build status](https://ci.appveyor.com/api/projects/status/github/softethervpn/softethervpn?branch=master&svg=true)](https://ci.appveyor.com/project/softethervpn/softethervpn) [![Travis CI build status](https://travis-ci.org/SoftEtherVPN/SoftEtherVPN.svg?branch=master)](https://travis-ci.org/SoftEtherVPN/SoftEtherVPN) [![Coverity Scan Build Status](https://scan.coverity.com/projects/16304/badge.svg)](https://scan.coverity.com/projects/softethervpn-softethervpn)
+[![AppVeyor build status](https://ci.appveyor.com/api/projects/status/github/softethervpn/softethervpn?branch=master&svg=true)](https://ci.appveyor.com/project/softethervpn/softethervpn) [![Travis CI build status](https://travis-ci.org/SoftEtherVPN/SoftEtherVPN.svg?branch=master)](https://travis-ci.org/SoftEtherVPN/SoftEtherVPN) [![gitlab-ci build status](https://gitlab.com/SoftEther/SoftEtherVPN/badges/master/build.svg)](https://gitlab.com/SoftEther/SoftEtherVPN/pipelines) [![Coverity Scan Build Status](https://scan.coverity.com/projects/16304/badge.svg)](https://scan.coverity.com/projects/softethervpn-softethervpn)
 
 - [SoftEther VPN](#softether-vpn)
 - [BOARD MEMBERS OF THIS REPOSITORY](#board-members-of-this-repository)