PSA: Dropping Support for Ubuntu 18.04

We hate to have to do this so suddenly, but due to the changes made to the FTL build containers, and issues reported to us on Discourse we will need to drop support for Ubuntu 18.04 going forward. While Ubuntu 18.04 is still LTS, there are still two further releases (20.04 , and 22.04), so we would encourage users to upgrade to one of those.

That said, there were no breaking changes in FTL for v5.17,  please revert to the previous version by running:

pihole checkout ftl v5.16.3

If the above command causes an error, please modify line 171 of /opt/pihole/piholeCheckOut.sh to read oldbranch="$(pihole-FTL -b || echo master)" (see this comment for details)

In investigating this issue, we have revealed a gap in our test process that should have caught this well before we released. We’re aiming to get that patched so that we don’t run into this for future releases.