Support LOCK/UNLOCK verbs.

[the-maldridge]

I'd like to add support for the LOCK/UNLOCK HTTP verbs as I am developing an application that expects to consume these verbs before synchronizing a conflicting operation on shared state. Prior to adding this support to Echo I'd like to gain some agreement that a patch will be accepted for this functionality as there is not an http.MethodLock constant in the net/http library. I can either add this method in the constants in echo.go or I can add it inline.

[lammel]

It would only make sense to support WebDAV as a whole as these methods are defined in RFC 4918: HTTP Extensions for Web Distributed Authoring and Versioning (WebDAV)

This is more or less a duplicate of #1459 which requested WebDAV support, but went stale.

A PR would definitely be welcome and considered for full WebDAV support. Go core libs shall be reused as much as possible though and dependencies must be kept to a minimum to avoid bloat.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[aldas]

closing, from v4.8.0 this is possible. See #2237