Integrate CentOS7+ into CI testing

[tomeichlersmith]

Is your feature request related to a problem? Please describe.
Related to bug caught by @omar-moreno in #36 . Different OS+compilers have different search paths. Expanding our testing should be helpful to this end.

Describe the solution you'd like
Add more OS options to the test job. We can use the container option to specify an OS not offered by GitHub runners themselves.

Describe alternatives you've considered
Alternative is not to include these OS's in CI testing. I think we can make the decision on OS on a case-by-case basis, but CentOS is heavily used in the community so it should definitely be included.

[tomeichlersmith]

Operating systems

• Alpine
• CentOS7
• CentOS Stream 8
• Ubuntu
• Mac OS

Compilers (where appropriate)

• gcc
• clang

Maybe do matrix of valid compiler versions per OS like HighFive