Update ghcr.io/cloudflare/origin-ca-issuer-charts/origin-ca-issuer Docker tag to v0.6.4 (#3943)

Co-authored-by: thecluster-bot[bot] <98929874+thecluster-bot[bot]@users.noreply.github.com>

Author: thecluster-bot[bot]

flux/infrastructure/controllers/cloudflare-system/oci-repository.yml

@@ -10,4 +10,4 @@ spec:
     mediaType: application/vnd.cncf.helm.chart.content.v1.tar+gzip
     operation: copy
   ref:
-    tag: 0.6.2
+    tag: 0.6.4