Fix 3.7 broken pipeline again4

.gitlab-ci.yml

@@ -13,6 +13,7 @@
       - apt-get update
       - pip install --upgrade pip
       - pip install typing-extensions
+      - pip install pypdf2
       - pip install -U git+https://github.com/TeskaLabs/asab
       - pip install flake8
       - pip install jinja2