fix: lookup volumename on pvc

This should fix cases with helm trying to override volumeName, which is an immutable field.

Author: archer-65

charts/kubernetes-agent/templates/tentacle-pvc.yaml

@@ -10,11 +10,13 @@ spec:
     {{- .Values.persistence.accessModes | toYaml | nindent 4 }}
   {{- with .Values.persistence.storageClassName }}
   storageClassName: {{ . | quote }}
-  {{- end }}  
-  {{- with .Values.persistence.volumeName }}
-  volumeName: {{ . | quote }}
+  {{- end }}
+  {{- if .Values.persistence.volumeName }}
+  volumeName: {{ .Values.persistence.volumeName | quote }}
+  {{- else if (lookup "v1" "PersistentVolumeClaim" .Release.Namespace (include "kubernetes-agent.pvcName" .)) }}
+  volumeName: {{ (lookup "v1" "PersistentVolumeClaim" .Release.Namespace (include "kubernetes-agent.pvcName" .)).spec.volumeName }}
   {{- end }}
   resources:
     requests:
       storage: {{ .Values.persistence.size}}
-{{- end }} 
+{{- end }}