Update dependencies

vendor/github.com/prometheus/common/model/labelset.go

@@ -17,6 +17,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"sort"
+	"strings"
 )
 
 // A LabelSet is a collection of LabelName and LabelValue pairs.  The LabelSet
@@ -128,6 +129,16 @@ func (l LabelSet) Merge(other LabelSet) LabelSet {
 	return result
 }
 
+func (l LabelSet) String() string {
+	lstrs := make([]string, 0, len(l))
+	for l, v := range l {
+		lstrs = append(lstrs, fmt.Sprintf("%s=%q", l, v))
+	}
+
+	sort.Strings(lstrs)
+	return fmt.Sprintf("{%s}", strings.Join(lstrs, ", "))
+}
+
 // Fingerprint returns the LabelSet's fingerprint.
 func (ls LabelSet) Fingerprint() Fingerprint {
 	return labelSetToFingerprint(ls)