Add SSH key for user dkh21

roles/devops-ssh-users/defaults/main.yml

@@ -33,6 +33,9 @@ devops_users:
   - name: 'Ujjwal Das'
     username: ukd20
     pub_key: ukd20-2.pub
+  - name: 'Dave Hart'
+    username: dkh21
+    pub_key: dkh21.pub
 
 ssh_revoked_keys:
   - username: si202