Add gnocchi to required projects

The latest release of gnocchi is not installable
due to the protobuf version we use in upper constraints.
This change adds gnocchi as a required project so that
it will be cloned by Zuul and added to LIBS_FROM_GIT

Depends-On: https://review.opendev.org/c/openstack/devstack/+/872902

Change-Id: Ie70fec0a79b8c9ba1354cf32d6740ac710976c5c
diff --git a/.zuul.yaml b/.zuul.yaml
index 133d300..b970649 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -22,6 +22,7 @@
       - openstack/dib-utils
       - openstack/diskimage-builder
       - openstack/tempest
+      - gnocchixyz/gnocchi
     vars:
       configure_swap_size: 8192
       devstack_plugins:
@@ -76,6 +77,7 @@
       - openstack/dib-utils
       - openstack/diskimage-builder
       - openstack/tempest
+      - gnocchixyz/gnocchi
     vars: &base_vars
       configure_swap_size: 8192
       devstack_plugins: