make ReadWriteMany the default accessMode

with this MR, I am making ReadWriteMany to the default accessmode as we have a new storage cluster now

{{cookiecutter.project_slug}}/templates/{{cookiecutter.template_base_name}}/persistentvolumeclaims.yaml

@@ -32,7 +32,7 @@ spec:
   accessModes: {{ toYaml $options.accessModes | nindent 4 }}
   {{- else }}
   accessModes:
-    - ReadWriteOnce
+    - ReadWriteMany
   {{- end }}
   {%- endraw %}
   resources: