ARM64 linux build

[toaster42]

Describe your feature request

I would like to see an ARM64 build for Linux made available.

What problem does this feature solve?

ARM64/aarch64 platform builds for Linux, and especially Debian and Raspbian would allow less technically proficient end-users on Raspberry Pi (running Raspbian) or ARM64 ChomeOS devices(via crostini) to run marktext without needing to figure out how to manually build it.

Additional Context

I was able to glean the corrective steps from issue #2558, and this comment on an issue with fpm.

Steps to build on ARM64:

In order to get the build process to complete I had to manually install two dependencies:

1. yarn seems to have issues in Debian (sudo apt install yarn installs cmdtest which contains a different tool also called yarn)

sudo apt remove cmdtest <-- only req'd if yarn was installed from default Debian repo
sudo apt remove yarn && curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
sudo apt-get update && sudo apt-get install yarn

And with that, yarn install works. The above could possibly be replaced with npm install -g yarn, but I did not test that. Unfortunately, yarn run build still errors out because:
2. fpm had to be manually installed as the build process downloaded and tried to install the x86_64 build.

sudo apt install ruby
sudo gem install fpm
export USE_SYSTEM_FPM=true
export GEM_HOME="$(ruby -e 'puts Gem.user_dir')"
export PATH="$PATH:$GEM_HOME/bin"

From this point yarn run build still ends with an error as Debian lacks the rpm packaging tools, but it successfully built the AppImage, tar.gz, and .deb packages, which was good enough for me.