New features:
- new matcher feature, allowing to create a Responder based on net/http.Request content (header or body for example), so not only on method and URL as before. See the following new registering functions & methods:
- add following Responder methods, allowing to easily add some headers to the returned net/http.Response without the need to craft a Responder by hand:
Miscellaneous:
- documentation now uses new go1.19 doc features;
- go minimal version required is now 1.13;
- CI tests using go1.20 & golangci-lint v1.51.0.