ci: Limit depth of subprojects when cloning

Use the depth= argument from Meson 0.52 to limit the clone depth of
subprojects to 1. This should make the CI images a little smaller, and
reduce the bandwidth required to build them (although that’s not so
important because it only happens once every few months).

Similarly, only clone to a depth of 1 in `cache-subprojects.sh`, which
is run once every few months.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

.gitlab-ci/cache-subprojects.sh

@@ -2,7 +2,7 @@
 
 set -e
 
-git clone https://gitlab.gnome.org/GNOME/glib.git
+git clone --depth 1 --no-tags https://gitlab.gnome.org/GNOME/glib.git
 meson subprojects download --sourcedir glib
 rm glib/subprojects/*.wrap
 mv glib/subprojects/ .

subprojects/gtk-doc.wrap

@@ -2,3 +2,4 @@
 directory=gtk-doc
 url=https://gitlab.gnome.org/GNOME/gtk-doc.git
 revision=master
+depth=1

subprojects/libffi.wrap

@@ -2,3 +2,4 @@
 directory=libffi
 url=https://gitlab.freedesktop.org/gstreamer/meson-ports/libffi.git
 revision=meson
+depth=1

subprojects/proxy-libintl.wrap

@@ -2,3 +2,4 @@
 directory=proxy-libintl
 url=https://github.com/frida/proxy-libintl.git
 revision=0.1
+depth=1

subprojects/sysprof.wrap

@@ -2,3 +2,4 @@
 directory=sysprof
 url=https://gitlab.gnome.org/GNOME/sysprof.git
 revision=6b1cd7a722fcebae1ac392562c47957477ade8bf
+depth=1