Update weed/s3api/chunked_reader_v4_test.go

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

weed/s3api/chunked_reader_v4_test.go

@@ -243,7 +243,7 @@ func createTrailerStreamingRequest(t *testing.T, useValidTrailerSignature bool)
 	chunk1DataLenHex := fmt.Sprintf("%x", chunk1DataLen)
 
 	// Use current time for signatures
-	now := time.Now().UTC()
+	now, _ := time.Parse(iso8601Format, "20240115T150405Z")
 	amzDate := now.Format(iso8601Format)
 	dateStamp := now.Format(yyyymmdd)