Revert "changed SDK version from 1.6.1 to 1.4.4, which closes #7"

This reverts commit 9e9b0bf.

Author: Lea Steffen

.gitlab-ci.yml

@@ -1,7 +1,7 @@
 image: ubuntu:xenial
 
 variables:
-  SDK_VERSION: 1.4.4
+  SDK_VERSION: 1.6.1
 
 before_script:
   - pushd ${HOME}