The issue was that only the actual title was converted to uppercase, but
not the prefix as specified in `WORK_IN_PROGRESS_PREFIXES`. As a result,
the following did not work:
WORK_IN_PROGRESS_PREFIXES=Draft:,[Draft],WIP:,[WIP]
One possible workaround was:
WORK_IN_PROGRESS_PREFIXES=DRAFT:,[DRAFT],WIP:,[WIP]
Then indeed one could use `Draft` (as well as `DRAFT`) in the title.
However, the link `Start the title with DRAFT: to prevent the pull request
from being merged accidentally.` showed the suggestion in uppercase; so
it is not possible to show it as `Draft`. This PR fixes it, and allows
to use `Draft` in `WORK_IN_PROGRESS_PREFIXES`.
Fixes#19779
Ondřej Čertík