Will there be an update to the kernel (4.15.0-33-generic) when updating from 18.04.1 LTS to 18.04.2 LTS?
4.15 is the long term kernel for 18.04. It will receive regular updates for the entire 5 year public support for Ubuntu.
So just keep on updating and you will get the latest of the 4.15 series.
18.04.2 comes by default with the 18.10 kernel and graphics called HWE. About every 3 months after the regular release ubuntu HWE users will get the next kernel and graphics stack. So expect kernel v5 in July/August.
You can upgrade to the HWE if you want to. Its optional. Instructions and a summary for new 18.04.2 users are on our release blog