calico: fix warnings (#7121)

TASK [network_plugin/calico : Calico | Configure calico network pool] **********
task path: /builds/kargo-ci/kubernetes-sigs-kubespray/roles/network_plugin/calico/tasks/install.yml:138
Friday 08 January 2021  17:10:12 +0000 (0:00:01.521)       0:11:36.885 ********
[WARNING]: The value {'kind': 'IPPool', 'apiVersion': 'projectcalico.org/v3',
'metadata': {'name': 'default-pool'}, 'spec': {'blockSize': 24, 'cidr':
'10.233.64.0/18', 'ipipMode': 'Always', 'vxlanMode': 'Never', 'natOutgoing':
True}} (type dict) in a string field was converted to "{'kind': 'IPPool',
'apiVersion': 'projectcalico.org/v3', 'metadata': {'name': 'default-pool'},
'spec': {'blockSize': 24, 'cidr': '10.233.64.0/18', 'ipipMode': 'Always',
'vxlanMode': 'Never', 'natOutgoing': True}}" (type string). If this does not
look like what you expect, quote the entire value to ensure it does not change.

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>