crates: Use looseversion.LooseVersion2 to parse crate versions

packaging.version.parse is dedicated to parse Python package version
numbers but crate versions do not necessarily respect Python version
number conventions and thus some crate versions cannot be parsed.

Prefer to use looseversion.LooseVersion2 instead which in a drop-in
replacement for deprecated distutils.version.LooseVersion and enables
to parse all kind of version numbers.

requirements.txt

@@ -3,6 +3,7 @@ dateparser
 dulwich
 iso8601
 launchpadlib
+looseversion
 lxml
 psycopg2
 pyreadr