Add missing makedepends 'glib2-devel'

Fixes:

samu: job failed: /usr/bin/python /build/cinnamon-screensaver/src/cinnamon-screensaver-6.2.0/libcscreensaver/g-codegen.py org.cinnamon.SettingsDaemon.KeybindingHandler cs-keybinding-handler-proxy '--annotate org.cinnamon.SettingsDaemon.KeybindingHandler org.gtk.GDBus.C.Name KeybindingHandler' /build/cinnamon-screensaver/src/build/libcscreensaver ../cinnamon-screensaver-6.2.0/libcscreensaver/org.cinnamon.SettingsDaemon.KeybindingHandler.xml libcscreensaver/cs-keybinding-handler-proxy.h libcscreensaver/cs-keybinding-handler-proxy.c
Traceback (most recent call last):
  File "/build/cinnamon-screensaver/src/cinnamon-screensaver-6.2.0/libcscreensaver/g-codegen.py", line 26, in <module>
    subprocess.call([
  File "/usr/lib/python3.12/subprocess.py", line 389, in call
    with Popen(*popenargs, **kwargs) as p:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/subprocess.py", line 1026, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.12/subprocess.py", line 1955, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'gdbus-codegen'
samu: subcommands failed
==> ERROR: A failure occurred in build().
    Aborting...