Expose persistence.volumeName (#471)

### Benefits

possibly fix #470

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/471
Co-authored-by: pat-s <[email protected]>
Co-committed-by: pat-s <[email protected]>

templates/gitea/pvc.yaml

@@ -17,7 +17,9 @@ spec:
   {{- if .Values.persistence.storageClass }}
   storageClassName: {{ .Values.persistence.storageClass }}
   {{- end }}
-  volumeName: ""
+  {{- with .Values.persistence.volumeName }}
+  volumeName: {{ . }}
+  {{- end }}
   resources:
     requests:
       storage: {{ .Values.persistence.size }}