Version update message for older stacks

[lee212]

To encourage using the latest version of RCT, it is useful if a version check is enabled with a message to update.

[iparask]

@lee212, can you provide an example of how you think this might work? I think we may have to go to all tags and add a warning.

[mturilli]

@lee212 ping

[lee212]

pip warning would be a good example like:

WARNING: You are using pip version 19.2.3, however version 19.3.1 is available.

from https://github.com/pypa/pip/blob/master/src/pip/_internal/self_outdated_check.py

[iparask]

Alright! Does it make sense to include from Jan 2021 release onwards or update all previous releases as well?

[andre-merzky]

We actually had this implemented with a -v flag on radical-stack which checked pypi for the latest available version. Alas, the pypi interface we used for this became deprecated, and thus a recent PR (radical-cybertools/radical.utils/pull/276) removes that support again until we find a different way to query that information (in a timely and simple fashion).