minor update of dependencies on stfc-cloud-cert-manager chart

Author: github-actions[bot]

charts/stfc-cloud-cert-manager/Chart.yaml

@@ -1,11 +1,9 @@
 apiVersion: v2
-name: stfc-cloud-cert-manager
-version: 1.2.0
-description: A Helm chart to deploy opinionated instance of cert-manager for the STFC Cloud
-type: application
-
 dependencies:
-# https://github.com/cert-manager/cert-manager/releases
   - name: cert-manager
-    version: 1.15.3
     repository: https://charts.jetstack.io
+    version: v1.17.1
+description: A Helm chart to deploy opinionated instance of cert-manager for the STFC Cloud
+name: stfc-cloud-cert-manager
+type: application
+version: 1.2.1