macosx plugin: Set miminum system version for the mozilla plugin as well.

(cherry picked from commit 7f43b934)
Signed-off-by: Derk-Jan Hartman <hartman@videolan.org>

extras/package/macosx/plugin/Info.plist.in

@@ -26,5 +26,7 @@
 	<string>@VERSION@</string>
 	<key>CSResourcesFileMapped</key>
 	<true/>
+	<key>LSMinimumSystemVersion</key>
+	<string>10.5.0</string>
 </dict>
 </plist>