Update docs; macOS 10.13 is the minimum supported version.

Author: sa666666

Announce.txt

@@ -28,7 +28,7 @@ distributions currently available are:
       Stella-7.0-x64.exe     (64-bit EXE installer)
       Stella-7.0-windows.zip (64 bit ZIP version)
 
-  * Binary distribution for macOS 10.12 and above :
+  * Binary distribution for macOS 10.13 and above :
       Stella-7.0-macos.dmg (ARM M1 and 64-bit Intel)
 
   * Binary distribution for 64-bit Ubuntu :

docs/index.html

@@ -368,9 +368,9 @@ <h3><b><u>Macintosh</u></b></h3>
   <p>The Mac version of Stella is designed to work on an Apple Macintosh with
   the following:</p>
   <ul>
-    <li>macOS 10.11 or above</li>
+    <li>macOS 10.13 or above</li>
     <li>64-bit ARM or Intel processor</li>
-    <li>Xcode 13.0 is required to compile the Stella source code</li>
+    <li>Xcode 16.0 is required to compile the Stella source code</li>
   </ul>
 
   <p>