Apparently _0 doesn't work for CLIENTCAS

plays/docker/service.yaml

@@ -9,7 +9,7 @@
       env:
         REGISTRY_HTTP_TLS_CERTIFICATE: /certs/fullchain.pem
         REGISTRY_HTTP_TLS_KEY: /certs/privkey.pem
-        REGISTRY_HTTP_TLS_CLIENTCAS_0: /certs/ca.pem
+        REGISTRY_HTTP_TLS_CLIENTCAS: " - /certs/ca.pem"
       publish: [
         { published_port: 5000, target_port: 5000 }
       ]