Upgrade to Go 1.18 and re-vendor dependencies

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

@@ -74,7 +74,7 @@ func parseBuddyInfo(r io.Reader) ([]BuddyInfo, error) {
 		for i := 0; i < arraySize; i++ {
 			sizes[i], err = strconv.ParseFloat(parts[i+4], 64)
 			if err != nil {
-				return nil, fmt.Errorf("invalid value in buddyinfo: %s", err)
+				return nil, fmt.Errorf("invalid value in buddyinfo: %w", err)
 			}
 		}