Update outdated action versions

[gnadt]

Made the following changes:

Minor updates to remove warnings

Update workflow action versions

Make ALSA_PLUGIN_DIR env variable available during precompilation

[bramtayl]

Ok as long as you've verified that you can still use ALSA plugins with this change. I'm a little unsure whether modifying the environment will work as part of the module, seems a bit safer to do during initialization? Maybe make ALSA_PLUGIN_DIR const since it's now a global variable? Why do you need it to be available during precompilation?

[gnadt]

On Linux, no the ALSA plugins can't be used. I don't think they could before either, but there are no CI results to look at. That change didn't resolve the issue, I've tried a bunch of things in my fork, nothing seems to get PortAudio to precompile on Linux. Potentially some issue with using dlopen on the ALSA plugin library files, but I'm not familiar with that.

[bramtayl]

Last time I checked the alsa plugins bit was working? If that particular change doesn't help precompilation, I'd say we shouldn't do it.

[gnadt]

On Linux it was working? If so, please re-run the Tests workflow without any changes so there's a baseline