pencil2d
Use Rocky Linux container for Linux nightly builds
This PR moves the Linux nightly builds to Rocky Linux. By doing this, we can build on a system that is still receiving support, while still maintaing a low glibc version for maximum compatibility. The low glibc version version is critical for appimage builds as they will only run on systems with a glibc version equal to or greater than the one it was built with. A list of the main version changes that accompany this switch is listed below.
The only functional change I am aware of is that the version of gstreamer good plugins provided by Rocky Linux's repositories lacks the jack plugin. As far as I can tell this is an oversight upstream and hasn't be reported. I don't think this is a blocker as it is unlikely many of our appimage users are using a sound server targeted towards audio professionals.
Version Changes
Qt 5 Build
Qt: 5.15.2 -> 5.15.3 glibc: 2.23 -> 2.28 Examples of supported distros: Ubuntu 18.04+, Debian >= Buster, Fedora 29+ As far as I can tell all the systems we would be dropping with this change have been EOL for multiple years already.
Qt 6 Build
Qt: 6.2.4 -> 6.6.2 glibc: 3.35 -> 3.34 Examples of supported distros: Ubuntu 21.10+, Debian >= Bookworm, Fedora 35
