Add a page explaining that XP/2003 are no longer supported

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

Gruntfile.js

@@ -11,6 +11,12 @@ module.exports = function(grunt) {
 					src: ['governance-model.md'],
 					dest: 'governance-model.html'
 				}]
+			},
+			requirements: {
+				files: [{
+					src: ['requirements.md'],
+					dest: 'requirements.html'
+				}]
 			}
 		},
 

requirements.md

@@ -0,0 +1,11 @@
+# Prerequisites
+
+This page lists the prerequisites required to run [Git for Windows](https://git-for-windows.github.io/).
+
+## Windows version
+
+As of Git for Windows v2.10.1, Windows Vista or later are required. The last version of Git for Windows to support Windows XP and Windows Server 2003 is [v2.10.0](https://github.com/git-for-windows/git/releases/tag/v2.10.0.windows.1).
+
+Why?
+
+Parts of Git are implemented in shell script, and Git for Windows runs those scripts via [MSYS2](https://msys2.github.io/)'s POSIX emulation layer, which in turn is based on the [Cygwin POSIX emulation layer](https://cygwin.com). Seeing as Windows XP and Windows Server 2003 are years past their official end of life, the Cygwin project ended their Herculean efforts to support those Windows versions.