docs: Allow plain certs for CA cluster issuer inventory (#678)

Co-authored-by: okozachenko1203 <okozachenko1203@users.noreply.github.com>
diff --git a/roles/cluster_issuer/tasks/type/ca/main.yml b/roles/cluster_issuer/tasks/type/ca/main.yml
index dd5394b..a52b70a 100644
--- a/roles/cluster_issuer/tasks/type/ca/main.yml
+++ b/roles/cluster_issuer/tasks/type/ca/main.yml
@@ -22,7 +22,7 @@
           name: "{{ cluster_issuer_ca_secret_name }}"
           namespace: cert-manager
         type: kubernetes.io/tls
-        data:
+        stringData:
           tls.crt: "{{ cluster_issuer_ca_certificate }}"
           tls.key: "{{ cluster_issuer_ca_private_key }}"