Create release script

Also remove the extras from pyproject.toml as those seem buggy:

python-poetry/poetry#2073
python-poetry/poetry#1145

DEVELOPING.md

@@ -9,30 +9,8 @@ $ tox
 
 ## Releasing
 
-Prerequisites:
-
- 1. Ensure we're on branch main (`git branch`).
- 1. Ensure the repo is clean (`git status`).
- 1. Ensure all the tests pass (`tox`).
-
 ```console
-$ poetry version <bump>
-$ git add pyproject.tml && git commit -m "vX.X.X release"
-$ git tag -a vX.X.X -m "vX.X.X release"
-
-$ # Create Docker image.
-$ docker build -t ghcr.io/sprt/skippex:X.X.X .
-$ # Test image.
-$ docker run --rm --network host --entrypoint sh ghcr.io/sprt/skippex:X.X.X -c ". /venv/bin/activate && python -m pytest"
-$ # Tag image with "latest".
-$ docker tag ghcr.io/sprt/skippex:X.X.X ghcr.io/sprt/skippex:latest
-$ # Publish on PYPI.
-$ poetry publish --build
-$ # Publish on GitHub Container Registry.
-$ docker push ghcr.io/sprt/skippex:X.X.X
-$ docker push ghcr.io/sprt/skippex:latest
-$ # Push to git repo.
-$ git push --follow-tags
+$ python release.py
 ```
 
 ## Building a development Docker image

pyproject.toml

@@ -25,13 +25,11 @@ xdg = "^5.0.1"
 pid = "^3.0.4"
 
 [tool.poetry.dev-dependencies]
-ipython = { version = "<7.17", optional = true }  # Python 3.6 support was removed in v7.17.
+ipython = "<7.17"  # Python 3.6 support was removed in v7.17.
 pytest = "^6.2.1"
 tox = "^3.21.1"
 tox-poetry-dev-dependencies = "^0.0.9"
-
-[tool.poetry.extras]
-ipython = ["ipython"]
+subprocess-tee = "^0.2.0"
 
 [tool.pytest.ini_options]
 filterwarnings = [