Use the same syntax as was already in the bug template because some
people are still leaving out the howto text in the middle of their own
bug/feature description.
Add a note asking bug reporters to test with the latest stable version
of GIMP or with dev code (not with old stable versions).
Also add some labels on bug reports and feature requests.
We realize that gitlab doesn't encourage people to give base information
as software version or operating system.
Issue templates are not perfect but better than nothing.