Feature: add CI/CD workflows

[ShoGinn]

I have checked all the prerequisites below and I'm yet experiencing a problem

• [x] Read the README.md
• [x] Have the extended version of Hugo installed
• [x] Used the exampleSite's config.toml as a reference
• [x] I have included my repository link. Instead of pasting long snippets here.

Describe the bug

I have noticed during my development of this theme that there are easily caught problems if you just run it through a workflow.

Propose: use the workflows I recommend in my repo.

https://github.com/ShoGinn/hugo-clarity/tree/add_workflows

In the repo you see that I tried to fix the test.yml and incorporate an html linter.

[ShoGinn]

With these workflows you can see errors that exist currently in the theme for the exampleSite that should be remedied.

(essentially any thumbnail with a relative url has a 404 error)

[rootwork]

OK so just to be clear what is being proposed (@ShoGinn let me know if I make any mistakes here):

• .github/dependabot.yml opts in to Dependabot.
• .github/workflows/continuous-deployment.yml replaces our current .github/workflows/test.yml. Instead of just trying to run a generic Hugo build, it actually builds the site for production and does a test deploy (to GitHub Pages).
• .github/workflows/continuous-integration.yml builds the site and uses the Ruby gem html-proofer to test for valid HTML. This would also be the action that we could add other sorts of testing on, presumably.

I think these are probably good starting points. I don't know if it matters what framework we use for testing -- obviously there are lots of HTML validation/testing tools in JS/Node, Go, Ruby, Bash, whatever we want to run. Here we would be using Ruby but I feel agnostic about that, and we could always swap it out in the future if we wanted.

As these are all in our .github dir they're all internal to the project and wouldn't affect how end-users use the theme.

Assigning @chipzoller @onweru to basically do a review, and then @ShoGinn you could cut a PR from that branch.

[ShoGinn]

@rootwork I concur with your assertions, the html-proofer is kinda the gold-standard and I think in a build environment we aren't making it a pre-req but just an executable test.

Standing by for approval.

[chipzoller]

I also think these are good things. Contributions would be most welcome to help improve the experience with Clarity!

[rootwork]

@ShoGinn Would you like to make a PR for these? If not I can make one based on your workflows, but since it's your idea I wanted to invite you to take the credit 🥇