Issue548 gh pages in master

[jsmailes]

What does this implement/fix? Explain your changes.

Changes the process of building and deploying documentation so make build-gh-pages is no longer necessary.

The contents of the gh-pages branch has been moved to the docs folder in the master branch.

On push to the master branch (or when a pull request is merged with master), a GitHub Action is triggered which pushes any changes to the docs folder to the gh-pages branch.

This does not change behaviour of the site and does not require any configuration changes, but it improves the repository's usability by getting rid of the need to keep track of two long-live branches.

Does this close any currently open issues?

This closes issues #484 and #548 by unifying the gh-pages and master branches and automating updates of the site based on changes to the master branch.

Any relevant logs, error output, etc?

(If it’s long, please paste to https://ghostbin.com/ and insert the link here.)

Any other comments?

It may be possible to make this change using Travis instead of GitHub Actions if desired.

I am more familiar with GitHub Actions so that's what I've used here, but I imagine it would be possible to get the same results with a Travis configuration file.

[joshrabinowitz]

@jsmailes thank you for this PR! I really appreciate it.

Can you please give detailed instructions how I should test this branch?

I'm sort of drawing a blank -- I don't typically use git hooks or github actions -- but maybe I should!

[sobolevn]

Great work! 👍

[sobolevn]

We don't have any submodules. So, this can be skipped (I guess).

[joshrabinowitz]

@sobolevn did you test this branch?

[sobolevn]

Not yet.

[joshrabinowitz]

Update for @jsmailes - I'll look at this in depth after we get the next release out.

[joshrabinowitz]

OK, I've looked this over.

The ideal solution, I think, would be to stop using the gh-pages branch all together, and instead put all the files for git-secret.io in a directory somewhere like .gh-pages/, in the master branch.

Is this doable?

[sobolevn]

Yes, github can build docs from docs/ folder from the master branch now.

[joshrabinowitz]

I think we should do what @sobolevn describes above, and use the (magical) /docs folder in master instead of the magical gh-pages branch

@jsmailes, would you be amenable to re-doing this PR using just the /docs folder and without depending on the gh-pages branch?