package/enet: bump to version 1.3.18

See:
https://github.com/lsalzman/enet/blob/v1.3.18/ChangeLog

Update file hash due to update license dates:
https://github.com/lsalzman/enet/commit/2662c0de09e36f2a2030ccc2c528a3e4c9e8138a

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/enet/enet.hash

@@ -1,3 +1,3 @@
 # Locally computed
-sha256  a38f0f194555d558533b8b15c0c478e946310022d0ec7b34334e19e4574dcedc  enet-1.3.17.tar.gz
-sha256  77f94e3be39938801163844b8bf9a4f12badcc0da136e9886e7da14a816d74d3  LICENSE
+sha256  2a8a0c5360d68bb4fcd11f2e4c47c69976e8d2c85b109dd7d60b1181a4f85d36  enet-1.3.18.tar.gz
+sha256  a29cd246638974da7c6edf423a0a69d4a6f7d759940b7cfa9a2bc3442ac3834c  LICENSE

package/enet/enet.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-ENET_VERSION = 1.3.17
+ENET_VERSION = 1.3.18
 ENET_SITE = http://enet.bespin.org/download
 ENET_LICENSE = MIT
 ENET_LICENSE_FILES = LICENSE