go.mod: update to github.com/emicklei/go-restful/v3 v3.7.3

full diff: https://github.com/emicklei/go-restful/compare/v2.9.5...v3.7.3

- Switch to using go modules
- Add check for wildcard to fix CORS filter
- Add check on writer to prevent compression of response twice
- Add OPTIONS shortcut WebService receiver
- Add Route metadata to request attributes or allow adding attributes to routes
- Add wroteHeader set
- Enable content encoding on Handle and ServeHTTP
- Feat: support google custom verb
- Feature: override list of method allowed without content-type
- Fix Allow header not set on '405: Method Not Allowed' responses
- Fix Go 1.15: conversion from int to string yields a string of one rune
- Fix WriteError return value
- Fix: use request/response resulting from filter chain
- handle path params with prefixes and suffixes
- HTTP response body was broken, if struct to be converted to JSON has boolean value
- List available representations in 406 body
- Support describing response headers
- Unwrap function in filter chain + remove unused dispatchWithFilters

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

go.mod

@@ -26,7 +26,7 @@ require (
 	github.com/docker/go-events v0.0.0-20190806004212-e31b211e4f1c
 	github.com/docker/go-metrics v0.0.1
 	github.com/docker/go-units v0.4.0
-	github.com/emicklei/go-restful v2.9.5+incompatible
+	github.com/emicklei/go-restful/v3 v3.7.3
 	github.com/fsnotify/fsnotify v1.5.1
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/gogo/googleapis v1.4.0