The release picked for build is based on release date, not version number

[James Simpson]

LATEST_RELEASE=$(curl https://api.github.com/repos/prometheus/prometheus/releases/latest -s | jq -r .tag_name)

The above line will cause a newly released bugfix of a lower version (i.e. 2.37.1) to be selected for build over the highest available version (i.e. 2.38.0).

This has the potential to cause issues where we build a new version with the snap which includes breaking changes, and then accidentally revert to a lower version later.

[James Simpson (jsimpso)]

We should instead look for both the highest release:
HIGHEST_RELEASE=$(curl https://api.github.com/repos/prometheus/prometheus/releases -s | jq -r .[].tag_name | grep '^v2\.[0-9]*\.[0-9]*$' | sort -nr | head -n1)

We should then prefer the highest release for automatic builds to the edge channel.

The "latest release" could still be useful - we should monitor which minor versions we have releases for and automatically build/publish revisional releases for those versions to the appropriate channel.