chore: Improving Github Actions code

[michelboaventura]

• Properly formatting
• master -> main
• Update ubuntu from 20.04 to latest
• Update actions to newest version
• Running lints and generation with elixir 1.17 and otp 27
• Replace deprecated ::set-output with env vars

I didn't add elixir 1.17 to the test matrix because I'd have to remove 1.14 since 1.17 isn't compatible with OTP 24which is required for 1.14. If we decide to drop 1.14 support we could do it.

[doomspork]

Thank you @michelboaventura 🙏 However, going forward we are planning to manage these from a common repository, Common Config, as we've done with ExMachina and others: .github/workflows/common-config.yaml. My plan is to start that process this weekend so

I'm going to close this but welcome you taking a look at our Common Config repo and seeing whether there are opportunities there to improve our actions. Alternatively, if you'd like to kick off the CC work on this repo feel free to do so, an example can be found here

[michelboaventura]

Sure thing! I was hoping that with this PR the action that generates new lib versions would start working again so we could solve this issue too! I think it makes total sense to have a common config since there are so many projects within beam-community.