Add tox and gitlab CI configuration

.gitlab-ci.yml

+image: python:latest
+
+cache:
+  paths:
+    - .tox
+
+stages:
+  - test
+  - publish
+
+before_script:
+  - apt-get update -yqq
+    && apt-get install -yqq --no-install-recommends
+    make
+    g++
+    && apt-get autoremove -yqq --purge
+    && apt-get clean
+
+unittests:
+  stage: test
+  script:
+    - pip install tox==4.12
+    - tox -v -e pytest
+
+pypi_publish:
+  before_script:
+   - pip install twine
+  only:
+   - master
+  stage: publish
+  when: on_success
+  script:
+    - pip install twine
+    - python setup.py sdist bdist_wheel
+    - python -m twine upload
+     --skip-existing
+     --repository-url https://pypi.clarin-pl.eu/
+     -u $PIPY_USER
+     -p $PIPY_PASS
+     dist/combo*.whl

setup.cfg

-[aliases]
-test=pytest
-
-[tox:tox]
-envlist = py38
-skipsdist = True
-
-[testenv:pytest]
-deps = pytest
-commands = pytest
-
-[metadata]
-description-file = README.md

tox.ini

+[tox]
+envlist = py38,py39,py310
+
+[testenv]
+deps = pytest
+commands = pytest {posargs}
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