Github actions to check lesson builds

[colinsauze]

There should be some github actions to check the lesson builds correctly and passes make lesson-check.

Examples on doing this available from: https://github.com/carpentries-incubator/template/tree/gh-pages/.github/workflows

[maxim-belkin]

This lesson doesn't pass the website action check because there is no Gemfile. You can get it from https://github.com/carpentries/styles.

[colinsauze]

Thanks @maxim-belkin but its still failing to run lesson-check, any ideas why?

[vinisalazar]

This check indicates that lesson-check is passing (albeit with warnings), am I missing anything?

[maxim-belkin]

Thanks @maxim-belkin but its still failing to run lesson-check, any ideas why?

I do see the reason (explained below) but I'm pretty sure make lesson-check-all should not fail no matter what. I'll fix that (in carpentries/styles).

Explanation: make lesson-check-all currently fails because all lines in 05-dimensionality-reduction.md are empty. If you add even a single dot or an empty HTML comment <!-- --> -- it'll succeed. PR #21 adds some text there, so the check passes there

[colinsauze]

I've just seen that error about dimensonality-reduction missing a blank line too. I was expecting it to appear if you expanded the "Run make lesson-check all" section, but I just see it saying (in red) "Error: ". But when I view the raw logs by pressing the 3 dots at the top of the check screen I can see that error.