Update README.md

Author: KiyoLelou10

task-07/README.md

@@ -70,7 +70,7 @@ gnrc_pktbuf_release(pkt);
 * Have a look in `udp.c` how packets are constructed and send
 * Compile, flash, and run on the board `BOARD=samr21-xpro make all flash term`
 * Type `help`
-* Start UDP server on port 8888 using `udp server start 8808`
+* Start UDP server on port 8888 using `udp server start 8888`
 * Get your IPv6 address using `ifconfig`
 * Send your neighbor some messages using `udp send`