make nut06 fields optional (#157)

06.md

@@ -80,14 +80,14 @@ With the mint's response being of the form `GetInfoResponse`:
 }
 ```
 
-- `name` is the name of the mint and should be recognizable.
-- `pubkey` is the hex pubkey of the mint.
-- `version` is the implementation name and the version of the software running on this mint separated with a slash "/",
-- `description` is a short description of the mint that can be shown in the wallet next to the mint's name.
-- `description_long` is a long description that can be shown in an additional field.
-- `contact` is an array of contact objects to reach the mint operator. A contact object consists of two fields. The `method` field denotes the contact method (like "email"), the `info` field denotes the identifier (like "[email protected]").
-- `modt` is the message of the day that the wallet must display to the user. It should only be used to display important announcements to users, such as scheduled maintenances.
-- `nuts` indicates each NUT specification that the mint supports and its settings. The settings are defined in each NUT separately.
+- (optional) `name` is the name of the mint and should be recognizable.
+- (optional) `pubkey` is the hex pubkey of the mint.
+- (optional) `version` is the implementation name and the version of the software running on this mint separated with a slash "/".
+- (optional) `description` is a short description of the mint that can be shown in the wallet next to the mint's name.
+- (optional) `description_long` is a long description that can be shown in an additional field.
+- (optional) `contact` is an array of contact objects to reach the mint operator. A contact object consists of two fields. The `method` field denotes the contact method (like "email"), the `info` field denotes the identifier (like "[email protected]").
+- (optional) `motd` is the message of the day that the wallet must display to the user. It should only be used to display important announcements to users, such as scheduled maintenances.
+- (optional) `nuts` indicates each NUT specification that the mint supports and its settings. The settings are defined in each NUT separately.
 
 With curl: