Merge branch 'add_pipeline_badge' into 'master'

Update README.md to indicate that our gitlab pipeline is building

See merge request OpenMW/openmw!1734

README.md

@@ -1,7 +1,7 @@
 OpenMW
 ======
 
-[![Build Status](https://api.travis-ci.org/OpenMW/openmw.svg)](https://travis-ci.org/OpenMW/openmw) [![Build status](https://ci.appveyor.com/api/projects/status/github/openmw/openmw?svg=true)](https://ci.appveyor.com/project/psi29a/openmw)  [![Coverity Scan Build Status](https://scan.coverity.com/projects/3740/badge.svg)](https://scan.coverity.com/projects/3740)
+[![Build Status](https://api.travis-ci.org/OpenMW/openmw.svg)](https://travis-ci.org/OpenMW/openmw) [![Build status](https://ci.appveyor.com/api/projects/status/github/openmw/openmw?svg=true)](https://ci.appveyor.com/project/psi29a/openmw)  [![Coverity Scan Build Status](https://scan.coverity.com/projects/3740/badge.svg)](https://scan.coverity.com/projects/3740) [![pipeline status](https://gitlab.com/OpenMW/openmw/badges/master/pipeline.svg)](https://gitlab.com/OpenMW/openmw/commits/master)
 
 OpenMW is an open-source game engine that supports playing Morrowind by Bethesda Softworks. You need to own the game for OpenMW to play Morrowind.