minor fix in CI

.gitlab-ci.yml

@@ -262,7 +262,7 @@ sync-gitlab-spack-instance:
     - spack repo list | grep -q ebrains-spack-builds && echo "Repository registered already" || spack repo add $SPACK_REPO_PATH
     - spack repo list
     # install compiler (if not already installed)
-    - EBRAINS_SPACK_COMPILER=$(grep 'compiler' $CI_PROJECT_DIR/packages.yaml | awk -F'[][]' '{ print $2 }')
+    - EBRAINS_SPACK_COMPILER=$(grep 'compiler' $CI_PROJECT_DIR/site-config/$SYSTEMNAME/packages.yaml | awk -F'[][]' '{ print $2 }')
     - spack compiler find
     - spack install $EBRAINS_SPACK_COMPILER
     - spack load $EBRAINS_SPACK_COMPILER