DOC: note -s ours merge of maintenance branch

The -s ours merge allows us to merge later from the maintenance branch
if there's any useful work on there.
DOC: update copyright dates; note need to check

We need to update the year on the copyright dates from time to time.
DOC: reminder to update AUTHORs and THANKS
Merge branch 'maint/0.3.x' into main-master

* maint/0.3.x:
  DOC: reminder to update AUTHORs and THANKS
  DOC: update copyright dates; note need to check
  DOC: note -s ours merge of maintenance branch