CI: Reinstall python packages

Reinstall python packages inside the virtualenv to have more control on versions

.gitlab-ci.yml

@@ -10,12 +10,12 @@ run-tests:
   stage: test
   script:
     - rm -rf civenv-master
-    - virtualenv --system-site-packages civenv
+    - virtualenv -p python3 --system-site-packages civenv
     - . ./civenv/bin/activate
-    - pip3 install mypy
-    - pip3 install git+https://dev.gajim.org/gajim/python-nbxmpp.git@master --upgrade
-    - pip3 install pylint==2.4.4
-    - /home/gitlab-runner/.local/bin/mypy gajim
+    - pip3 install -I mypy
+    - pip3 install -I git+https://dev.gajim.org/gajim/python-nbxmpp.git@master
+    - pip3 install -I pylint==2.4.4
+    - mypy gajim
     - scripts/dev/pylint-ci.sh --jobs=2 gajim
     - python3 setup.py test -s test.no_gui
     - deactivate