v6.2.2

[major] NewRouter function now accepts variadic Routes instead of slice of Routes (breaking change)
[minor] Router now has a convenience method Add(routes...*Route)
[minor] Route grouping feature added (usage available in the sample app, cmd/main.go)
[-] updated tests
[-] fixed module version in go.mod
[-] fixed v6 imports
[patch] fixed middleware not applied on routegroups