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* Restore behaviour of ignoring requirements declared with `Pip VCS support <https://pip.pypa.io/en/stable/topics/vcs-support/>`__, and extend it to new and old syntax.
* Read all installed packages with ``importlib.metadata``, rather than trying to look up by name.
This allows pip-lock to work for packages that have a dot in their name, which ``pip-compile`` normalizes to a dash.