CI workflow to upload to pypi on creation of a release

[php1ic]

Initial upload to pypi was done manually. Create a new CI pipeline to automate this process when we create a release.

[SuperSubatomic]

This would be great - it's a really helpful library. I wanted to use AtomicMass, but looks like there was an error in the parsing (that's since been fixed). Currently using AMEMassExcess as (an admittedly easy) work around.