Remove default volume read_only

It was always setting to true

nomad/service.nomad

@@ -55,7 +55,7 @@ job "[[.name]]" {
     [[ range $v := . | parseJSON -]]
     volume "[[ $v.name ]]" {
       type = "host"
-      read_only = [[ default true $v.read_only ]]
+      read_only = [[ $v.read_only ]]
       source = "[[ $v.name ]]"
     }
     [[ end ]]
@@ -160,7 +160,7 @@ job "[[.name]]" {
       volume_mount {
         volume = "[[ $v.name ]]"
         destination = "[[ $v.dest ]]"
-        read_only = [[ default true $v.read_only ]]
+        read_only = [[ $v.read_only ]]
       }
       [[ end ]]
       [[ end -]]