v5.0.0rc2

What's Changed

• Support multi content type in request body and responses by @luolingchun in #214
• Fix the trailing / caused by register_api with url_prefix by @luolingchun in #268
• Add test with openapi-spec-validator by @luolingchun in #269
• Fix summary and description in __doc__ by @luolingchun in #270

Full Changelog: v5.0.0rc1...v5.0.0.rc2