meson,ci: bump meson req for rusticl to 1.2

Signed-off-by: Karol Herbst <git@karolherbst.de>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21451>

meson.build

@@ -764,8 +764,8 @@ if with_gallium_rusticl
     error('rusticl requires at least one gallium driver.')
   endif
 
-  if meson.version().version_compare('< 1.0.0')
-    error('rusticl requires meson 1.0.0 or newer')
+  if meson.version().version_compare('< 1.2')
+    error('rusticl requires meson 1.2.0 or newer')
   endif
 
   add_languages('rust', required: true)