Specify package versions for dependencies

[timofeymukha]

Hello!

pyroms seems to require pinning the versions of several packages.

The latest setuptools is not supported (distutils issue), version 70 seems to work.
For bathy_smoother matplotlib==3.2 seems to work, but not later due to from matplotlib.cbook import dedent being deprecated.

For pyroms/pyroms I'm having compilation issues, during f2py stuff it seems. Do you require particular compilers / version of f2py etc?

Providing this info in the readme would be very helpful! Thank you.