`gh-pages` size

[t-bltg]

Not a concern atm, but the documentation files for previous versions are kept in gh-pages (currently 1.25.6, 1.25.7).
We probably don't want gh-pages to grow infinitely an retain only the latest (currently 1.25.7).

@BeastyBlacksmith, this is probably related to 5c8d531 ?

[BeastyBlacksmith]

not that much related to that, but yes, we should think about a way to remove the old versions in an automatic manner, however the only way I am currently aware that it actually reduces the repo size is by rewriting history.

[t-bltg]

@BeastyBlacksmith, I'm starting to see failures, on the 10min imposed timeout for deployment.

E.g. https://github.com/JuliaPlots/PlotDocs.jl/actions/runs/3266291654/jobs/5370253574.

So I'm going to delete some old obsolete versions docs ?

[t-bltg]

Current status:

$ git checkout --track upstream/gh-pages
$ du -sh * | sort -h
[...]
65M	v1.25.12
65M	v1.26.0
157M	v1.30.2
171M	v1.31.7
171M	v1.32.1
171M	v1.33.0
174M	v1.34.4
179M	v1.35.8
182M	dev
182M	v1.36.3
196M	v1.27.6
196M	v1.28.2
196M	v1.29.1