Flask-openapi3

- [13](https://github.com/luolingchun/flask-openapi3/issues/13) drop support for flask 1.0.x. Thanks, danmur
- [15](https://github.com/luolingchun/flask-openapi3/pull/15) Fix to enable BaseModel with `__root__` property. Thanks, tarcisiojr
- [14](https://github.com/luolingchun/flask-openapi3/pull/14) Custom parameters: doc_prefix, api_doc_url, swagger_url, redoc_url, rapidoc_url. Thanks, barryrobison
- Upgrade swagger UI v4.6.2
- Upgrade Redoc v2.0.0-rc.63
- Upgrade RapiDoc v9.2.0

- add operation_id for OpenAPI Specification

- [10](https://github.com/luolingchun/flask-openapi3/issues/10) Fix: header's title case. Thanks, rrr34
- [9](https://github.com/luolingchun/flask-openapi3/issues/9) Support for extra responses. Thanks, blynn99
- [12](https://github.com/luolingchun/flask-openapi3/pull/12) Support for path operation field deprecated. Thanks, blynn99
- Add keyword parameters `summary` and `description`
- Add servers for OpenAPI
- Upgrade swagger UI v4.1.3
- Upgrade Redoc v2.0.0-rc.59
- Add rapidoc

Breaking Changes

- Renamed `securitySchemes` to `security_schemes`
- Renamed `docExpansion` to `doc_expansion`

- fix: default value in a query and form model
- fix: empty form and body
- support `from __future__ import annotations`
- drop python36

- add Configuration `docExpansion`
- query and form add array support

- fix: path $ref
- fix: markdown enum