Update README, compatible was improved in recent versions

Author: PeterDaveHello

README.md

@@ -58,8 +58,6 @@ Please note that [certain colors](https://github.com/PeterDaveHello/ColorEchoFor
 ## Notes
 
 * If you have [lolcat](https://github.com/busyloop/lolcat), you can also try `echo.Rainbow`.
-* If you are using Mac OS, please upgrade your bash first, you can use [Homebrew](http://brew.sh/) or [MacPorts](https://www.macports.org/), the origin bash is too old.
-* `ksh`/`sh` shell's color echo may rely on external `/bin/echo`, it may not work properly with color under BSD and Mac OS.
 
 ## Screenshot