Update cert-manager to v1.18.1 (#859)

Co-authored-by: JohnGarbutt <[email protected]>

Author: azimuth-automation-bot[bot]

roles/certmanager/defaults/main.yml

@@ -3,7 +3,7 @@
 # The chart to use
 certmanager_chart_repo: https://charts.jetstack.io
 certmanager_chart_name: cert-manager
-certmanager_chart_version: v1.17.2
+certmanager_chart_version: v1.18.1
 
 # Release information for the cert-manager release
 certmanager_release_namespace: cert-manager