Changes to GET /data/readings

the response property items/items/allOf[subschema #2]/completeness became nullable for the status 200

the response property items/items/allOf[subschema #2]/date became nullable for the status 200

the response property items/items/allOf[subschema #2]/dateTime became nullable for the status 200

the response property items/items/allOf[subschema #2]/quality became nullable for the status 200