Consider updating CONTRIBUTING.md

[jangondol]

First of all, thumbs up to @rchampieux on creating and updating CONTRIBUTING.md! Very useful and friendly, I like it. 👍

One idea: the current version does not seem to talk about the licensing of submissions. It may be an overkill to introduce CLAs from a practical perspective (although maybe not from the legal perspective) but perhaps it may be useful to at least include in CONTRIBUTING.md that any submissions to the project will be subject to the licensing terms in LICENSE.md?

IANAL, so having someone more experienced (a lawyer? or @txtbks?) put this in better language would help. This may still not be fully enforceable from a legal perspective anyway (at least in some jurisdictions) but I think it may be useful to mention the issue of licensing upfront.

[rchampieux]

Thanks @jangondol! This is really helpful feedback. I will bring your suggestion to the rest of the team for review and action. 😸