[CRITICAL for new releases] Missing requirement 'importlib-metadata'

[lfwa]

The newly updated loggerutil.py requires the package importlib-metadata to log the version of carbontracker that was used. This dependency is not added to pyproject.toml, which means that any new releases from the master branch will be broken (the current PyPi version 1.1.6 is fine since it is based on an old version).

However, if we add importlib-metadata as a dependency then we can no longer support Python 3.6 and instead have to require Python $\geq$ 3.7. Native support of importlib.metadata is also introduced in Python $\geq$ 3.8 without requiring any additional packages, but again that means we have to drop support for Python 3.6 and 3.7.

If we wish to support (the very old) Python 3.6 going forward, an alternative would be to either remove logging of the version number or store it explicitly (and keep it updated through a script on new releases --- not great).

To reiterate, do not issue any new releases from the master branch until this issue is fixed!