eloomi v3 docs: Update an assignment

Request

PATCH https://api.eloomi.com/v3/courses/{courseId}/participants/{userId}

Parameter name	Value	Description	Additional
courseId	string	eloomis ID for the course	Required
userId	string	eloomis ID for the user	Required

Parameter name	Value	Description	Additional
ClientId	string	Provided by eloomi	Required
Authorization	string	Look in the documentation for the authentication endpoint on how to construct this	Required

{
    "customAttributes": {
        "{key}": "string"
    },
    "deadline": "YYYY-MM-DD",
    "required": "number"
}

Name	Example	Description	Additional
customAttributes			Optional
customAttributes.{key}		Keys and value depend on platform and course	Optional
deadline	"2020-12-13"	Date for when the course should be completed	Optional
required	1	Flag to indicate if the course is mandatory or not Possible values are: `%!s(float64=0)` `%!s(float64=1)`	Optional

The following HTTP status codes may be returned, optionally with a response resource.