update zstd --fast benchmark result

use --fast=4, instead of --fast=3,
to make it more representative of a lzo equivalent scenario.

Author: Cyan4973

README.md

@@ -45,8 +45,8 @@ on the [Silesia compression corpus].
 | brotli 1.1.0 -1         | 2.883 |   290 MB/s |   425 MB/s |
 | [zlib] 1.3.1 -1         | 2.743 |   105 MB/s |   390 MB/s |
 | **zstd 1.5.7 --fast=1** | 2.439 |   545 MB/s |  1850 MB/s |
-| **zstd 1.5.7 --fast=3** | 2.241 |   635 MB/s |  1980 MB/s |
 | quicklz 1.5.0 -1        | 2.238 |   520 MB/s |   750 MB/s |
+| **zstd 1.5.7 --fast=4** | 2.146 |   665 MB/s |  2050 MB/s |
 | lzo1x 2.10 -1           | 2.106 |   650 MB/s |   780 MB/s |
 | [lz4] 1.10.0            | 2.101 |   675 MB/s |  3850 MB/s |
 | snappy 1.2.1            | 2.089 |   520 MB/s |  1500 MB/s |