[openwrt/openwrt] README: replace "MacOSX" with "macOS"

[LEDE Commits]

aparcar pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/3e3e1b8bab94d5eb162604d4c198b426761598d7

commit 3e3e1b8bab94d5eb162604d4c198b426761598d7
Author: Gentry Deng <me at gend.moe>
AuthorDate: Sun Mar 31 21:42:12 2024 +0800

    README: replace "MacOSX" with "macOS"
    
    In October 2018, the last version of the operating system named "Mac OS X" ended its life cycle.
    
    It's time to change it to "macOS".
    
    Signed-off-by: Gentry Deng <me at gend.moe>
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 8bca0ee7b0..9141b2392d 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ An advanced user may require additional or specific package. (Toolchain, SDK, ..
 
 ## Development
 
-To build your own firmware you need a GNU/Linux, BSD or MacOSX system (case
+To build your own firmware you need a GNU/Linux, BSD or macOS system (case
 sensitive filesystem required). Cygwin is unsupported because of the lack of a
 case sensitive file system.