CI is currently broken

[jacobwilliams]

See: https://github.com/fortran-lang/minpack/pull/87/checks

Need fixing:

• gcc 10 no longer available?
• update the action version numbers
• provision-with-micromamba is deprecated

Notes:

• Can we just use conda to install gfortran for all platforms?

[jacobwilliams]

@awvwgk What is the purpose of this line:

        plat: manylinux${{ matrix.python == '3.6' && '2010' || '_2_12' }}_x86_64

If I want to update python versions, what are the 2010 and 2_12 tokens for?

[awvwgk]

This decides the platform tag, if we drop py36 we can probably get rid of this one line.