Upgrade to Go 1.18 and re-vendor dependencies

vendor/github.com/prometheus/procfs/net_sockstat.go

@@ -70,7 +70,7 @@ func readSockstat(name string) (*NetSockstat, error) {
 
 	stat, err := parseSockstat(bytes.NewReader(b))
 	if err != nil {
-		return nil, fmt.Errorf("failed to read sockstats from %q: %v", name, err)
+		return nil, fmt.Errorf("failed to read sockstats from %q: %w", name, err)
 	}
 
 	return stat, nil
@@ -90,7 +90,7 @@ func parseSockstat(r io.Reader) (*NetSockstat, error) {
 		// The remaining fields are key/value pairs.
 		kvs, err := parseSockstatKVs(fields[1:])
 		if err != nil {
-			return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %v", s.Text(), err)
+			return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %w", s.Text(), err)
 		}
 
 		// The first field is the protocol. We must trim its colon suffix.