changes to MR

2020/2020-03-30_basicGitTraining/slides/merge.md

-# Pull and merge requests
+# Merge (pull) requests
 
 If you want your changes to be reflected on the `develop` or `master` branches,
-**submit a PR** via the Github interface.
+**submit a merge request (MR)** via the git-r3lab interface.
 
 Use the **interface** to make use of your peers to review your code!
 <img src="slides/img/branch-merge.png" class="branch-merge" height="500em"/>