Default to parallel mode?

[mjankowski]

Happy to prepare PR for this, just wanted to confirm desirable first...

I believe rubocop defaults to parallel mode, and I expected haml-lint would as well (once I learned it had a parallel mode).

Any objection to changing that default?

[sds]

Supportive, though we may want to consider adding the ability to specify the level of parallelism, rather than always assuming the user wants to allocate all available CPUs. That said, not a blocker.

[mjankowski]

Great, started to put something together, will open PR when ready ... could maybe do env var or something as followup for the "how many CPUs" aspect (I think rubocop does that?)

Separately, I noticed a few other things while attempting to get set up, curious what if any of these you'd be open for PRs on...

• Some of the appraisal/gemspec/gemfile defs seem a little of out of sync?
• Haml 6.3 support missing from appraisals (and tool in general)?
• Ruby 3.3 and 3.4 missing from CI matrix

[sds]

• Updating the appraisal specs sounds great
• Adding HAML 6.3 + Ruby 3.3 + 3.4 to the build matrix seems reasonable

Thanks!

[sds]

Implemented in #541. Thank you.