miniupnpc: Update to version 2.2.3

Library code and public headers are now properly separated, we can fix include paths
to remove the redundant subfolder.

thirdparty/miniupnpc/src/addr_is_reserved.h

@@ -0,0 +1,14 @@
+/* $Id: $ */
+/* vim: tabstop=4 shiftwidth=4 noexpandtab
+ * Project: miniupnp
+ * http://miniupnp.free.fr/ or https://miniupnp.tuxfamily.org/
+ * Author: Thomas Bernard
+ * Copyright (c) 2005-2020 Thomas Bernard
+ * This software is subjects to the conditions detailed
+ * in the LICENCE file provided within this distribution */
+#ifndef ADDR_IS_RESERVED_H_INCLUDED
+#define ADDR_IS_RESERVED_H_INCLUDED
+
+int addr_is_reserved(const char * addr_str);
+
+#endif /* ADDR_IS_RESERVED_H_INCLUDED */