Changes to Difficulty adjustment history

added the non-success response with the status 500

added the optional property meta/stale_since to the response with the 200 status

added the optional property meta/data_age_days to the response with the 200 status

added the optional property meta/notes to the response with the 200 status

added the optional property meta/period to the response with the 200 status

the response property data/adjustments became optional for the status 200

the response property data/count became optional for the status 200

the response property data/interval became optional for the status 200

response property data/adjustments list-of-types was widened by adding types null to media type application/json of response 200

response property data/count list-of-types was widened by adding types null and number to media type application/json of response 200

response property data/interval list-of-types was widened by adding types null to media type application/json of response 200

added the optional property code to the response with the 401 status

added the optional property code to the response with the 429 status

added the optional property code to the response with the 503 status

added the optional property hint to the response with the 401 status

added the optional property hint to the response with the 429 status

added the optional property hint to the response with the 503 status

added the optional property plan to the response with the 401 status

added the optional property plan to the response with the 429 status

added the optional property plan to the response with the 503 status

added the optional property reason to the response with the 401 status

added the optional property reason to the response with the 429 status

added the optional property reason to the response with the 503 status