Adjust the depends of the GCC-8 cross compiler packages after the change
from pmbootstrap!1778. This does not have any effect (since the GCC-8
aports don't have !tracedeps in options, in contrary to the other GCC
aports we ship). But it makes sure that we don't get any changes after
running the repository maintenance script from here:
https://wiki.postmarketos.org/wiki/Repository_maintenance
[ci:skip-build]: cosmetic change, build would take too long anyway
