arch_release_promotion/release.py:
Add Metric, SizeMetric, AmountMetric and |VersionMetric| models,
that track metrics with size, amount or version (respectively).
Change the Release model to use amount_metrics, size_metrics and
version_metrics attributes instead of info.
arch_release_promotion/config.py:
Change the ReleaseConfig model to track version_metrics,
size_metrics and amount_metrics instead of info_metrics.
arch_release_promotion/files.py:
Change read_metrics_file() to return a tuple of AmountMetric,
SizeMetric and VersionMetric lists and read the provided file only if it
exists.
arch_release_promotion/cli.py:
Change main() to correctly initialize instances of Release with the
different types of metrics.
tests/*: Change the tests to match the changes in signature and attributes.
Fixes #11 (closed)