[xml] xmllint for GitHub Actions

[Piotr Bański <bansp o2 pl>]

Hi all,

Those of you using GitHub will have heard of GitHub Actions [1], which 
allow your pushes or pull requests to initiate a pretty wide variety of 
workflows.
I played with Actions a bit after listening to several talks at Virtual 
2020 [2] yesterday, and since my main interest is in TEI / XML 
modelling/infrastructures, I immediately hit the wall when trying to 
setup post-push XML validation -- because the virtual Ubuntu environment 
provided by GitHub lacks xmllint.
Going around that is relatively trivial even if silly, resource-wise 
(you basically need to get libxml2-utils reinstalled with each script 
application), but it looks like even that does not always succeed. I 
have now commented in a closed "wontfix" ticket [3] that refused to 
provide xmllint as part of the virtual setup, asking for 
reconsideration, and thought of giving a heads-up to this list, in case 
someone felt interested in adding their weight there. Maybe someone can 
come up with better arguments than I did, in case you also find yourself 
tied to GitHub despite its recent changes in the management/ownership.
It seems to me that part of the game concerns the place of XML 
technology in the awareness of the decision-makers at GitHub -- after 
one Virtual2020 talk, I enrolled, out of curiosity, in the beta 
programme of Codespaces (web-based IDEs integrated with GitHub), where I 
was asked to tick the language(s) that I would be interested to use with 
Codespaces. Among the various standard and exotic suggestions, I wasn't 
able to find XSLT. Maybe that shouldn't even be very surprising, but 
combined with the xmllint issue, it made me wish to remind the 
powers-that-be that not everything yet is made of JSON. So I'm sharing 
this sentiment with the list, in case someone feels similarly about this 
and envisions using xmllint in their Actions. Feel welcome to either 
post in [3] or create a new issue referencing it (re-opening was not an 
option, sadly, but maybe one of the maintainers will, seeing the traffic).
Cheers,

   Piotr

[1] https://github.com/features/actions
[2] https://githubsatellite.com/
[3] https://github.com/actions/virtual-environments/issues/423