Update README.md (#184)

Sync is tested on Windows 11 24H2

README.md

@@ -138,7 +138,7 @@ compare against the true GNU coreutils version on the Linux-based tests first.
 |         | stdbuf    | Run a command with modified I/O stream buffering |         |
 |         | stty      | Print or change terminal characteristics         |         |
 | ✓ | sum       | Print checksum and block counts                  | ✓ |
-| ✓ | sync      | Synchronize cached writes to persistent storage  |         |
+| ✓ | sync      | Synchronize cached writes to persistent storage  | ✓ |
 | ✓ | tac       | Concatenate and write files in reverse           | ✓ |
 | ✓ | tail      | Output the last part of files                    | ✓ |
 |         | tee       | Redirect output to multiple files or processes   | ✓ |
@@ -162,4 +162,4 @@ compare against the true GNU coreutils version on the Linux-based tests first.
 | ✓ | whoami    | Print effective user ID                          | ✓ |
 | ✓ | yes       | Print a string until interrupted                 | ✓ |
 
-Windows ✓ if the utility exists in the [Windows version of GNU coreutils](https://github.com/mingw-io/coreutils).
+Windows ✓ if the utility exists in the [Windows version of GNU coreutils](https://github.com/mingw-io/coreutils).