six again causing errors

.gitlab-ci.yml

@@ -42,7 +42,7 @@ tests (from scratch):
     - ./CI/update_badge.sh > /dev/null
   script:
     - pip install --upgrade pip
-    - pip install numpy
+    - pip install numpy wheel six
     - zypper --non-interactive install binutils libproj-devel gdal-devel
     - zypper --non-interactive install proj geos-devel
     #    - cat requirements.txt | cut -f1 -d"#" | sed '/^\s*$/d' | xargs -L 1 pip install