Images don't build due to ancient pinned versions

[WhyNotHugo]

The current way dependencies are pinned is completely broken; specific minor versions are pinned, but Alpine does not keep older package versions on all mirrors.

Since Alpine has updated the minor versions for most packages, many images fail to build.

I left a longer explanation in the PR that introduced the issue, but opening an issue for better visibility.

[WhyNotHugo]

Please note that pinning minor versions is an anti-pattern anyway; you want to ensure that the same major version is used, but do want to upgrade minors since they (a) are backwards-compatible (b) may include security fixes.

Alpine stable release channels stick to the same major version and won't break backwards-compatibility.