Since commit f469a9b9fc we support
automatically selecting the price list of the current date - but
we still only packaged pricelist.json and not those with more current
dates.
i.e. some added/removed products and some price changes
The package now supports multiple price lists and selects the right
one based on the effective date suffix (if present).
Prior to this commit, we useda custom modified versin of python-zeep
that accepts a list of headesr as part of the _soapheader argument.
Recent changes to python-zeep include that support natively using the
_soapeheaders [plural] argument. Port the code to that.