[gitlab-ci] Add missing build parameter to before_test script

.gitlab-ci.yml

@@ -72,7 +72,7 @@ stages:
     - ./_ci/install.sh _ci master #updates ci support scripts
     - ./_ci/before_build.sh
     - mv conda-bld ${CONDA_ROOT}
-    - ./scripts/before_test.sh
+    - ./scripts/before_test.sh build
   script:
     - export BEAT_DOCKER_TESTS=true
     - BOB_TEST_ONLY=true ./_ci/build.sh