chore(deps): update kubernetes-csi/external-snapshotter to v8.6.0

apps/templates/cert-manager-helm.yaml

@@ -12,7 +12,7 @@ spec:
   project: default
   source:
     repoURL: https://charts.jetstack.io
-    targetRevision: v1.21.2
+    targetRevision: v1.15.5
     chart: cert-manager
     helm:
       parameters:

apps/templates/snapshot-controller-helm.yaml

@@ -7,7 +7,7 @@ spec:
   project: default
   source:
     repoURL: https://github.com/kubernetes-csi/external-snapshotter.git
-    targetRevision: v8.2.1
+    targetRevision: v8.6.0
     path: deploy/kubernetes/snapshot-controller
   destination:
     server: https://kubernetes.default.svc