Update submodules to most recent commits in CI job

.gitlab-ci.yml

@@ -10,7 +10,9 @@ cache:
 before_script:
   - echo "Before script section"
   - export APT_CACHE_DIR=`pwd`/apt-cache && mkdir -pv $APT_CACHE_DIR
-  - apt-get update && apt-get -o dir::cache::archives="$APT_CACHE_DIR" -y install gnuplot gawk imagemagick poppler-utils
+  - apt-get update && apt-get -o dir::cache::archives="$APT_CACHE_DIR" -y install gnuplot gawk imagemagick poppler-utils git
+  - git submodule sync --recursive
+  - git submodule update  --remote --recursive
   - echo "Before script section END."
 
 after_script: