Use actions/github-pages to publish docs

[garryod]

Uses the official actions/github-pages action to publish docs to GitHub Pages. This should remove the need for gh-pages branch

[codecov]

Codecov Report

Merging #133 (796150e) into main (64d2a03) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main      #133   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         2           
  Lines           16        16           
=========================================
  Hits            16        16           

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[gilesknap]

At present this does not fit with the skeleton documentation model.

Skeleton keeps track of multiple versions of documentation and has a Docs Cleanup job to remove documentation on deleted branches. This all works vis the gh-pages branch that is not used by actions/github-pages. In future we could support the same features with actions/github-pages by fetching and mutating the documentation artifact. For now we will continue to use peaceiris/actions-gh-pages, in future this approach may be deprecated - review at this point.

[coretl]

Also, this PR broke the existing gh-pages deployment, I had to "unpublish", then change the gh-pages root and put it back to restore it.

[garryod]

Also, this PR broke the existing gh-pages deployment, I had to "unpublish", then change the gh-pages root and put it back to restore it.

Oops, sorry about that. Presumably the work of actions/configure-pages