gitlab-ci: no need to specify explicitly -Dbuildtype=debugoptimized.

This has now been changed to be the default meson build by Ell in the
previous commit.
5 jobs for master in 4 minutes and 51 seconds (queued for 1 second)
Status Job ID Name Coverage
  Dependencies
passed #479225
deps-git

00:04:51

failed #479226
deps-x86_64-w64-mingw32

00:01:48

 
  Gimp
skipped #479227
gimp-autotools
skipped #479228
gimp-meson
skipped #479229
gimp-x86_64-w64-mingw32-meson
 
Name Stage Failure
failed
deps-x86_64-w64-mingw32 Dependencies
The downloaded packages were saved in cache until the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'.
Error: Error downloading packages:
Status code: 503 for https://mirrors.fedoraproject.org/metalink?repo=updates-released-modular-f30&arch=x86_64
Uploading artifacts...
WARNING: .local/: no matching files
WARNING: _deps/: no matching files
ERROR: No files to upload
ERROR: Job failed: exit code 1