feat: add a minimal tox configuration

tox.ini

@@ -0,0 +1,51 @@
+[tox]
+min_version = 4.4.0
+envlist =
+    format
+    lint
+    dependencies
+    release-check
+
+[testenv:format]
+description = automatically reformat code
+skip_install = true
+deps =
+    pre-commit
+commands =
+    pre-commit run -a pyupgrade
+    pre-commit run -a isort
+    pre-commit run -a black
+
+[testenv:lint]
+description = run linters that will help improve the code style
+skip_install = true
+deps =
+    pre-commit
+commands =
+    pre-commit run -a
+
+[testenv:dependencies]
+description = check if the package defines all its dependencies
+skip_install = true
+deps =
+    build
+    z3c.dependencychecker==2.14.3
+commands =
+    python -m build --sdist
+    dependencychecker
+
+[testenv:release-check]
+description = ensure that the distribution is ready to release
+skip_install = true
+deps =
+    twine
+    build
+    towncrier
+
+commands =
+    # fake version to not have to install the package
+    # we build the change log as news entries might break
+    # the README that is displayed on PyPI
+    towncrier build --version=100.0.0 --yes
+    python -m build --sdist
+    twine check dist/*