Let Github actions rebuild web UI on push to web-src

[ejurgensen]

@hacketiwack I think it would be good if Github actions was used to automatically rebuild the web UI whenever a change is pushed to web-src. Thus, there is no relying on the build on a local machine, and the rebuilt UI can be kept out of a PR.

Let me know if you have any concerns about this.

[hacketiwack]

@ejurgensen, this situation bothered me for long and I'm glad that you tackled it.

I'm OK for this temporary solution.

But I have a guiding principle that says that no generated files must be placed in the source control repository.
Indeed, the build script of OwnTone, must include the generation of htdocs as well.
This would solve this work item as well.

I tried to fiddle around with the Makefile some months ago to not have to store the htdocs in the SCM.
But I wasn't successful at the time at finding a good example on how to do it.
Would it be possible for you to include the build of the Web UI within the Makefile?
Otherwise, I will continue my research.

Thanks in advance.

[ejurgensen]

But I have a guiding principle that says that no generated files must be placed in the source control repository.
Indeed, the build script of OwnTone, must include the generation of htdocs as well.

Yes, I agree, but it is difficult in practice. You may have seen PR #1439 where chme worked on this. One of the obstacles is that the node build needs to pull in resources from the internet. This doesn't work well with some package builders, and maybe it is also against Debian policies. I guess it also makes the build non-deterministic by nature, which is also against Debian policies, as I recall.

Would it be possible for you to include the build of the Web UI within the Makefile?

chme's PR does do this via ("make web"), so I can try to rebase it and merge it. Maybe it also needs some dusting off. But it will just mean that the assets can be built with "make web", it won't solve the issue of having generated files in the source.