build: replace verstion extraction via set to use python The version of roundup was extracted from roundup/__init__.py by sed. It is used to label the roundup.pot template file. Replaced the sed setup by importing roundup and printing the __Version__ variable. This should be less fragile to spacing and other changes.

Babel
Jinja2
MarkupSafe
Pygments
alabaster
certifi
charset-normalizer
docutils
idna
imagesize
packaging
pyparsing
requests
six
snowballstemmer
sphinxcontrib-applehelp
sphinxcontrib-devhelp
sphinxcontrib-htmlhelp
sphinxcontrib-jsmath
sphinxcontrib-qthelp
sphinxcontrib-serializinghtml
sphinxcontrib-websupport
urllib3