Remove unnecessary cache paths

.gitlab-ci.yml

 image: clarinpl/python:3.8
 
-variables:
-  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
-
 cache:
   paths:
     - .tox
-    - .cache/pip
-    - venv/
-
 stages:
   - publish
 
@@ -22,14 +16,14 @@ before_script:
 
 pypi_publish:
   before_script:
-   - pip3 list
-   - pip3 install twine
+   - pip list
+   - pip install twine
   only:
    - main
   stage: publish
   script:
-    - python3 setup.py sdist bdist_wheel
-    - python3 -m twine upload
+    - python setup.py sdist bdist_wheel
+    - python -m twine upload
      --skip-existing
      --repository-url https://pypi.clarin-pl.eu/
      -u $PIPY_USER