Linux guest support (two small changes)

[adil192]

Is your feature request related to a problem?

I want to use Linux instead of macOS since Linux is much faster.

I managed to hack it into working. I'll document my hacks here instead of a PR since I'm not overly familiar with Swift/macOS development.

What solution would you like?

1. getRunnerDownloadURL is hardcoded to use osx. Please can you make this configurable to linux?
   

   tartelet/Packages/GitHub/Sources/GitHubData/NetworkingGitHubClient.swift

   Line 70 in 178b765

   let os = "osx"

2. didConnect uses open -a Terminal ~/.start-runner.sh.
   

   tartelet/Packages/VirtualMachine/Sources/VirtualMachineDomain/GitHubActionsRunner/GitHubActionsRunnerSSHConnectionHandler.swift

   Line 117 in 178b765

   try await connection.executeCommand("open -a Terminal \(startRunnerScriptFilePath)")

   
   On Linux, this can be changed to just ~/.start-runner.sh.

What alternatives have you considered?

For now, I'm using these workarounds:

1. Install the runner manually with the instructions at https://github.com/organizations/saber-notes/settings/actions/runners/new?arch=arm64&os=linux (your URL will differ).

2. Add a shim at /usr/local/bin/open:

   #!/bin/bash
   # Tartelet tries to use `open -a Terminal ~/start-runner.sh`
   # but `open` doesn't exist on Linux. Fake it.
   
   set -e
   
   if [[ "$1" != "-a" ]]; then
     echo "open shim: expected -a as 1st arg" >&2
     exit 1
   fi
   if [[ "$2" != "Terminal" ]]; then
     echo "open shim: expected Terminal as 2nd arg" >&2
     exit 1
   fi
   if [[ -z "$3" ]]; then
     echo "open shim: missing command" >&2
     exit 1
   fi
   
   shift 2
   exec "$@"

   And of course make it executable chmod +x /usr/local/bin/open.

3. I also needed to install zsh.

Any additional context?

It works with these hacks: