gitlab: Updates classes in the issue template

This adds all the non-deprecated public classes to the issue template.
12 jobs for issue-template in 23 minutes and 13 seconds (queued for 16 minutes and 16 seconds)
Status Name Job ID Coverage
  Build
passed api-visibility #240120
librem5

00:03:01

passed build-debian-clang #240123
librem5

00:04:36

passed build-debian-gcc #240121
librem5

00:03:17

passed build-debian-gcc-static #240122
librem5

00:03:00

passed build-fedora-gcc #240124
librem5

00:03:40

 
  Test+Docs
passed build-gtkdoc #240125
librem5

00:02:52

passed unit-test #240126
librem5

00:02:37

43.8%
 
  Package
passed package-debian-buster #240127
librem5

00:02:27

passed package-debian-buster:arm64 #240128
librem5:arm64

00:07:55

passed package-flatpak #240129
flatpak

00:01:49

 
  Test Package
passed autopkgtest-debian-buster-package #240130
librem5

00:02:21

passed lintian-debian-buster-package #240131
librem5

00:00:53