build,meson: require libqmi 1.31.7, in sync with autotools

The required libqmi version was updated in configure.ac to 1.31.7 in
commit ac06052b97, but we forgot to do
the same in the meson setup.

meson.build

@@ -247,7 +247,7 @@ config_h.set('WITH_MBIM', enable_mbim)
 # QMI support (enabled by default)
 enable_qmi = get_option('qmi')
 if enable_qmi
-  qmi_glib_dep = dependency('qmi-glib', version: '>= 1.31.5')
+  qmi_glib_dep = dependency('qmi-glib', version: '>= 1.31.7')
 endif
 config_h.set('WITH_QMI', enable_qmi)