Merge pull request #25 from tyx/feature/road-to-sf4

Road to sf4

Merge pull request #23 from shouze/fix-a-415-http-code-handling-edge-…

…case

🐛 Fix a 415 http code handling edge case

Merge pull request #22 from shouze/fixup-previously-merged-pr-19

Fixup some forgot pieces of #19

Merge pull request #20 from shouze/fix/request-content-edge-case

🐛 Fix request content check edge case

Merge pull request #19 from shouze/upgrade-json-schema-dependency

Upgrade justinrainbow/json-schema >=3.0.0 <6.0.0

Merge pull request #14 from tyx/feature/readme

📖 Improve README