linux-mainline: update to 6.18.

Author: xJayMorex

srcpkgs/linux-mainline/template

@@ -1,6 +1,6 @@
 # Template file for 'linux-mainline'
 pkgname=linux-mainline
-version=6.17
+version=6.18
 revision=1
 metapackage=yes
 depends="linux${version} linux-base"