[SYCLomatic] Update README.md with platform requirements (#757)

Signed-off-by: Lu, John <[email protected]>

Author: LU-JOHN

README.md

@@ -38,9 +38,9 @@ expected to be similar to the daily releases.
 * `ninja` -
 [Download](https://github.com/ninja-build/ninja/wiki/Pre-built-Ninja-packages)
 * C++ compiler
-  * Linux: `GCC` version 7.1.0 or later (including libstdc++) -
+  * Linux: `GCC` version 7.5.0 or later (including libstdc++) -
     [Download](https://gcc.gnu.org/install/)
-  * Windows: `Visual Studio` version 15.7 preview 4 or later -
+  * Windows: `Visual Studio` 2019 or 2022 -
     [Download](https://visualstudio.microsoft.com/downloads/)
 
 ### Create SYCLomatic workspace