add `contentBoard` to possible title fields

[pschaub]

The TitleField contentBoard is missing here:

xbox-webapi-python/xbox/webapi/api/provider/titlehub/models.py

Lines 8 to 16 in 1a5aeb1

	class TitleFields(str, Enum):
	SERVICE_CONFIG_ID = "scid"
	ACHIEVEMENT = "achievement"
	STATS = "stats"
	GAME_PASS = "gamepass"
	IMAGE = "image"
	DETAIL = "detail"
	FRIENDS_WHO_PLAYED = "friendswhoplayed"
	ALTERNATE_TITLE_ID = "alternateTitleId"

Example:
https://titlehub.xboxlive.com/users/xuid(XUID)/titles/titlehistory/decoration/contentBoard