Multiarchitecture compatible container

[jerryhopper]

Hey there,
i wanted to run grav on my raspberryPi 4b (arm64), So i added a github-workflow that builds a multiarchitecture container.

[mwalbeck]

Hi, thank you for the contribution. I've been meaning to added an ARM build for quite a while but I just never got around to it. I currently run all builds on my own Drone CI instance and I would prefer to keep it that way as it makes it easier for me to maintain. Though just the other day I was playing around with getting buildx up and running with drone to build multiarch images, so since it was fresh in my mind I've switch to buildx for building the containers and added an arm64 build. It's ready to go on Docker Hub, though I haven't had a chance to test that it works as intended so let me know if you run into any issues.

[jerryhopper]

Hi, thanks for implementing arm64 builds. i understand your reasoning about your build-enviroment, i hoped the dockerfile-buildx would helped you with implementing arm65.

That said, i am encountering a problem when running the container - it gets stuck on 'install'

app_1  | 24 packages you are using are looking for funding.
app_1  | Use the `composer fund` command to find out more!
app_1  |
app_1  |
app_1  |
app_1  | In UniformResourceIterator.php line 102:
app_1  |
app_1  |   Failed to open dir: plugins:// does not exist.
app_1  |
app_1  |
app_1  | install [-s|--symlink] [-p|--plugin PLUGIN] [-t|--theme THEME] [--] []