Replace vbom.ml/util with fvbommel/sortorder

The vanity domain is down, and the project has moved
to a new location.

vendor check started failing because of this:

    Collecting initial packages
    Download dependencies
    unrecognized import path "vbom.ml/util" (https fetch: Get https://vbom.ml/util?go-get=1: dial tcp: lookup vbom.ml on 169.254.169.254:53: no such host)

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

cli/context/store/metadatastore.go

@@ -9,7 +9,7 @@ import (
 	"reflect"
 	"sort"
 
-	"vbom.ml/util/sortorder"
+	"github.com/fvbommel/sortorder"
 )
 
 const (