GP-0: Updating supported platforms in InstallationGuide

Author: ryanmkurtz

GhidraDocs/InstallationGuide.html

@@ -66,9 +66,9 @@ <h1>Ghidra Installation Guide</h1>
 
 <h2><a name="Platforms"></a>Platforms Supported</h2>
 <ul>
-  <li>Microsoft Windows 7 or later (64-bit)</li>
-  <li>Linux (64-bit, CentOS 7 is preferred)</li>
-  <li>macOS (OS X) 10.8.3+ (Mountain Lion or later)</li>
+  <li>Windows 7 or later (64-bit)</li>
+  <li>Linux (64-bit)</li>
+  <li>macOS 10.13 or later</li>
 </ul>
 <blockquote><p><b>NOTE: </b>All 32-bit OS installations are now deprecated. Please contact the
 Ghidra team if you have a specific need.</p></blockquote>