CI: added git submodule update --init

.gitlab-ci.yml

@@ -63,6 +63,7 @@ stages:
 
 .build_and_test_template: &build_and_test_definition
   - cd $CI_PROJECT_DIR
+  - git submodule update --init
   - mkdir -pv build
   - cd build
   - cmake -DCMAKE_BUILD_TYPE=release -DBUILD_EXAMPLES=ON -DBUILD_TESTS=ON ..