libxml2: bump the revision for icu update again.
libxml2: bump the revision for icu update again.

Now that icu57 devel packages are disabled, it should actually use
icu66.

haikuports/haikuports,haikuports/haikuports,haikuports/haikuports,haikuports/haikuports,Begasus/haikuports,moochris/haikuports,Begasus/haikuports,moochris/haikuports,Begasus/haikuports,Begasus/haikuports,moochris/haikuports,haikuports/haikuports,Begasus/haikuports