gitmodules: Correct libvirt-ci submodule URL

Correct the libvirt-ci repository URL to avoid this warning when
cloning / refreshing the submodule:

  warning: redirecting to https://gitlab.com/libvirt/libvirt-ci.git/

Fixes: 4ebb040 ("tests: integrate lcitool for generating build env manifests")
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220121154134.315047-3-f4bug@amsat.org>
Message-Id: <20220204204335.1689602-7-alex.bennee@linaro.org>

.gitmodules

@@ -66,4 +66,4 @@
 	url = https://gitlab.com/qemu-project/vbootrom.git
 [submodule "tests/lcitool/libvirt-ci"]
 	path = tests/lcitool/libvirt-ci
-	url = http://gitlab.com/libvirt/libvirt-ci
+	url = https://gitlab.com/libvirt/libvirt-ci.git