Add launchpadlib as a dep

This adds launchpadlib as a dep to jeepyb so that our assemble script
can install it alongside all the other jeepyb deps when building Gerrit
images. This way we don't need to install python3-launchpadlib anymore
and can use our base python images with Gerrit.

Depends-On: https://review.opendev.org/c/opendev/system-config/+/870118
Change-Id: I94fb9c7f16aa6c12840b54dac5e272950b4dea0c
diff --git a/requirements.txt b/requirements.txt
index 679b9ec..396b115 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -4,6 +4,7 @@
 pbr>=1.6
 
 gerritlib>=0.10.0
+launchpadlib>=1.10.13
 PyMySQL
 paramiko>=1.13.0
 PyGithub