Unable to update the kernel

I tried to follow the guide here: https://trisquel.info/en/wiki/update-linux-libre-kernel

but the $ sudo apt install --install-recommends linux-generic-hwe-8.0 xserver-xorg-hwe-16.04

command gave me this output:

Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
linux-generic-hwe-8.0 : Depends: linux-image-generic-hwe-8.0 (= 4.13.0.45.64+8.0trisquel4) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

I checked in synaptic package manager for broken packages, but seemingly there was none.

I recently installed Trisquel 8 and I believe it is the latest release.

The computer I am using is a MacBook Pro 9,1.