bug#50356: python-hy / python-funcparserlib / tox config file

[Vinicius Monego]

Fixed in 06e39eafd7d8279b0b97424c9c32f60a31bfce30 by updating
funcparserlib to the alpha version and Hy to 0.20.0. When the next
stable version of funcparserlib is released I will do another update.