Pin charmcraft to specific older version 2.2/stable

Change-Id: I1b380425a3dc435ea036f0944e8157f801daaf2d
diff --git a/playbooks/charm-cinder-storpool-iscsi/zaza-functional.yaml b/playbooks/charm-cinder-storpool-iscsi/zaza-functional.yaml
index 63a6fe3..3a1a4c2 100644
--- a/playbooks/charm-cinder-storpool-iscsi/zaza-functional.yaml
+++ b/playbooks/charm-cinder-storpool-iscsi/zaza-functional.yaml
@@ -3,7 +3,7 @@
     - name: A block
       block:
         - name: Install charmcraft
-          ansible.builtin.command: snap install charmcraft --classic
+          ansible.builtin.command: snap install charmcraft --classic --channel=2.2/stable
           become: true
 
         - name: Initialize lxd