Blender 2.8 requires Mac OS 10.7 or later

MacOS 10.7 “Lion” was the first to implement OpenGL 3.2, which will be
required to run Blender 2.8.

Minimum OS version was unspecified before.

release/darwin/blender.app/Contents/Info.plist

@@ -2,6 +2,8 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>LSMinimumSystemVersion</key>
+	<string>10.7.0</string>
 	<key>CFBundleDocumentTypes</key>
 	<array>
 		<dict>