Release 1.3 roadmap

[mperrin]

See also GitHub issues for release 1.3 and PRs for release 1.3.

PRs to complete and merge for this release:

• [x] #768 @obi-wan76
• [ ] #787 @mperrin
• [ ] #770 @mperrin
• [ ] #675 @mperrin

Tasks to do before release:

• [ ] NIRISS GR700XD model improvements. (not yet a PR) @obi-wan76
• [ ] add some smaller issues regarding improvements in a couple of function @obi-wan76
• [ ] Documentation about PSF subtraction examples @obi-wan76
• [ ] Notebook example on how to create very large PSFs @obi-wan76
• [ ] Data files update, needed for #770 and probably also the GR700XD