`GET /{collection}/{obj_uuid}/attributes/{attr}` return type is incorrect

[Apollo3zehn]

Sorry for spamming this project with issues! However I prefer to document my findings here to keep track of them.

The actual response of the GET /{collection}/{obj_uuid}/attributes/{attr} endpoint also returns a type property which is not documented here:

hdf-rest-api/openapi.yaml

Lines 2221 to 2232 in e6f1a68

	properties:
	created:
	type: number
	lastModified:
	type: number
	name:
	type: string
	shape:
	type: object
	value:
	type: string # TODO whatever the user put there?
	hrefs:

Additionally the openapi.yaml file defines that the value is of type string, but in my test setup the server (http://hsdshdflab.hdfgroup.org) returns an array of values. This leads to the problem that the returned json string cannot be deserialized properly (there is a type mismatch between string and array).