Include package building in `test.yml` workflow.

[esc]

The test.yaml workflow only tests the installation via pip and tests the software. As a developer I would like to see inclusion of testing the package building too to make sure that none of my PRs break packaging. The idea is to try to build a sdist and wheel for PyPi and a noarch package using conda and to check that these packages are sane, i.e. they can be installed and the included tests can be run successfully.