GitLab

This approach is more widely used and offers the same flexibility.

Closes: #35

For example the `package.json` could fail to be included in the git
commit, if `release-npm` was executed *after* `release-git`.
Now the order of targets is fixed.

Previously we did not handle the missing prefix "v" correctly for
MAKEFILET_DOWNLOAD_VERSION.

If downloaded version and current version matched exactly, then a
warning was emitted.

Closes: #21

Closes: #23

It is not a test, but just code style linting.

Shell-related testing and linting can be disabled via DISABLE_SHELL_CHECK=1.

Closes: #25

Closes: #26

The version requested via MAKEFILET_DOWNLOAD_VERSION may be newer than
the version available in a system-wide installed package.
Emit a warning in such a case.

Closes: #27

Closes: #29

The outdated SOURCES.txt file can lead to an incorrectly generated
source archive during "dist-python".

This is a workaround for https://github.com/pypa/setuptools/issues/436.

Closes: #33

A virtualenv does not necessarily include the pre-dependencies, e.g. in
case of a missing `--system-site-packages`.  Thus we install these
within the virtualenv.

Previously the wrong variable for tested and additionally "tox" was
always executed.

Now the dependency between "test" and "test-python" is only added if
DISABLE_PYTHON_TESTS is not "1" (by default: "0").

There are some circumstances (e.g. preferring site-wide packages), where
an automatic upgrade is not desirable.

The `/dev/null` target was not a good idea :(

This allows to emit helpful warnings in case of missing build
pre-dependencies, which need to be installed before the virtualenv is
created.

A typical set of pre-dependencies (`venv` and `wheel`) should be
suitable for most projects.