* ci: use generate-api-json to get api.json changes * restore copying default.yml * refactor: get api.json with single workflow * ci: api.jsonのdiffをbackendが変更されたときのみ取るように
* ci: use generate-api-json to get api.json changes * restore copying default.yml * refactor: get api.json with single workflow * ci: api.jsonのdiffをbackendが変更されたときのみ取るように