Added Laravel 8.0 to GitHub Actions

[roelofr]

I added Laravel 8.0 to the CI, but with an exception on PHP 7.2 (since it's not
supported by Laravel 8.0).

I also used the semver notation (^8.0) instead of the wildcard notation
(8.*) since Laravel has been Semver since 6.0.

[roelofr]

GitHub Actions seems to not have .github/ listed as one of the paths to trigger the pipeline, so I ran my own tests here.

[irazasyed]

Thanks @roelofr 👍

GitHub Actions seems to not have .github/ listed as one of the paths to trigger the pipeline

Yeah, Gotta update that but we've moved to its dedicated home as part of the major changes for the upcoming release of v4.x here. You're welcome to join there and create any PRs :)

[roelofr]

Yeah, I started working on a PR for the same purpose there, but the unit tests all failed 🙊

Is that still very much a WIP?

[irazasyed]

Tests are still WIP but the SDK itself is mostly completed and I don't see anymore changes happening for now and because of the major changes, the tests need to be rewritten.

@jonnywilliamson was working on some of the tests but definitely any additional helping hand with regard to the tests would greatly help us with the progress besides the docs that is pending.