CI: add missing git submodule init

debian/rules

@@ -5,6 +5,7 @@ export DH_VERBOSE = 1
 export DEB_BUILD_OPTIONS=parallel=4
 
 override_dh_auto_configure:
+	git submodule update --init --recursive
 	dh_auto_configure -- -DBUILD_SHARED_LIBS=ON -DCMAKE_BUILD_TYPE=RelWithDebInfo -DUA_NAMESPACE_ZERO=FULL -DUA_ENABLE_AMALGAMATION=OFF -DUA_PACK_DEBIAN=ON
 
 override_dh_auto_test: