Add arm64 build

[q4a]

I'm not sure why are you using container: ubuntu:xenial (trusty will reach End of Life in April 2026).
Since you are using Qt 5.9 and it's not aviable via ppa for xenial for arm64: I decided to add arm64 build using container: ubuntu:bionic while keeping container: ubuntu:xenial for amd64 version.

If you have any comments, please write and ping me.

[probonopd]

Is there a pressing need for this change?

[q4a]

Yes. I and other people require support for other archs ( according this #351 ). So I added arm64 support.
I can symplify code if you will agree to use container: ubuntu:bionic for amd64 as well.

[probonopd]

Ah, I had missed the point originally.
Yes, let's go bionic then.

[q4a]

Yes, let's go bionic then.

Done, I'm not sure about 1 line:
sudo apt-get update -qq
Should I keep it? (just in case)

[q4a]

BTW this PR will close issue #622

[probonopd]

I think sudo apt-get update -qq won't hurt.

[probonopd]

Looks like linuxdeployqt-continuous-aarch64.AppImage was built, very cool. Now it must only work as well ;-)

[q4a]

@probonopd I restored sudo apt-get update -qq
Also I tested linuxdeployqt-continuous-aarch64.AppImage from my repo:
I added arm64 support for VulkanCapsViewer, that uses linuxdeployqt.
If you have any arm64 SBC (like Raspberry Pi) you can get Vulkan_Caps_Viewer-wayland-aarch64.AppImage.ci-15 builded in this github CI
In my case it worked fine on Rock 5B (rk3588 arm SBC) and now I can upload my Vulkan stats (thanks to your repo and Sascha Willems app):
https://vulkan.gpuinfo.org/displayreport.php?id=39061

[probonopd]

Thank you very much @q4a

[q4a]

@probonopd Hi. Would you like to do some testing yourself or is there something else blocking this PR?

[probonopd]

Thank you very much @q4a