www/h2o: update 1.5.0 -> 1.5.2

• Update cmake args and regen cmake patch for the new release
• Add documentation files to pkg-plist

Changes: https://github.com/h2o/h2o/releases/tag/v1.5.1
Changes: https://github.com/h2o/h2o/releases/tag/v1.5.2

PR: 203956
Submitted by: Dave Cottlehuber <dch@skunkwerks.at> (maintainer)