vendor: update buildkit to 8effd45b

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/google/uuid/version4.go

@@ -27,8 +27,13 @@ func New() UUID {
 //  equivalent to the odds of creating a few tens of trillions of UUIDs in a
 //  year and having one duplicate.
 func NewRandom() (UUID, error) {
+	return NewRandomFromReader(rander)
+}
+
+// NewRandomFromReader returns a UUID based on bytes read from a given io.Reader.
+func NewRandomFromReader(r io.Reader) (UUID, error) {
 	var uuid UUID
-	_, err := io.ReadFull(rander, uuid[:])
+	_, err := io.ReadFull(r, uuid[:])
 	if err != nil {
 		return Nil, err
 	}