Use shell: bash when installing wheels in CIs

[andreped]

I observed an issue with installing compiled wheels in my test CIs in another project.

Apparently, pip ignores the --file-links argument if it finds a suitable wheel with the same name on PyPI. That means that it will ignore installing from the existing local wheel, and instead download the one on PyPI and install that one. This defeats the purpose of the test, as we are not testing the correct wheel!

This was solved by adding the -* wildcard fix like so package_name-* to the command. However, that fails in Powershell (on Windows). Thus, forcing the command to run with bash works for all operating systems.