Support route header value matches by regular expression #82
Description
Exact match semantics for route header values are not sufficient to cover all cases, such as server acceptable match for upgrade header with case-insensitive value websocket.
Currently to resolve the route, the route headers, and request headers are used, however, since the request headers value can be case sensitive, the checking condition can fail which will result in 404. This ticket is to track the ability to specify a regular expression for header values to cover all the case variations for example /[wW][eE][bB][sS][oO][cC][kK][eE][tT]/