using prebuild, static docker image

automation/Jenkinsfile

@@ -3,13 +3,7 @@ pipeline {
         BUILDDIR = 'build-tests'
     }
     agent {
-        dockerfile {
+        docker { image: fsfw-ci:d1}
-            dir 'automation'
-            //force docker to redownload base image and rebuild all steps instead of caching them
-            //this way, we always get an up to date docker image one each build
-            additionalBuildArgs  '--no-cache --pull'
-            reuseNode true
-        }
     }
     stages {
         stage('Clean') {