Add a CI workflow to build trunk-support on trunk

[shym]

This PR adds a CI workflow to build trunk-support on the latest trunk once a day and on updates on that branch. It also adds a badge to the README (hopefully I got those URLs right 🤔), which might help maintain the branch; and help users check whether possible issues were detected already.

[pitag-ha]

Nice, thank you, @shym!

I'm not sure about the badge either. The best way to find out is to merge and see.

[pitag-ha]

I love the time you've chosen for the run!

[pitag-ha]

I'm not sure either here. I was expecting something like

[![Build on `trunk`](https://img.shields.io/github/workflow/status//ocaml-ppx/ppxlib/
<I don't know what>?branch=trunk-support)](https://github.com/ocaml-ppx/ppxlib/
actions/workflows/build.yml)

Let's merge what you've put and see if it works!

[pitag-ha]

To follow up on this: It works! 🎉

[marrious11]

Hello @pitag-ha, I was looking at the CHANGES.me file.
Would it be nice to make the @mention user and #... issues as links?
For instance:

• Allow users to vendor ppxlib as-is, as well as ppx_sexp_conv in the same project (Allow users to vendor ppxlib as-is, as well as ppx_sexp_conv in the same project #386, @kit-ty-kate)

Instead of just:

• Allow users to vendor ppxlib as-is, as well as ppx_sexp_conv in the same project (#... issues, @mention user),
  which is not a link that can redirect one into the stated issue number easily

[marrious11]

@pitag-ha, my reason for this suggestion is that, if someone visits the CHANGES.me file, they should be able to see a summary of the status(merged, open, failed, etc.) for that particular issue.
Let me know what you think about it, please!

[pitag-ha]

Hi @marrious11, thanks for the suggestion! That's a good idea and, in fact, it's already the case. Let me explain. The purpose of the CHANGES.md is to generate the release notes when releasing ppxlib. You can have a look at our release notes here, where you can see that the PR tags automatically serve as links to the PRs.

Btw, just so you know: Outreachy applicants aren't expected to keep on working on the projects once the contribution period is over. And any contributions you do now, won't be taken into account in the intern selection process. Also, we don't want to take advantage of applicants working more on our projects than expected. That being said, if you'd love to keep on working on ppxlib/PPXs out of interest and to learn more, you're welcome to do so. I just wanted to be clear that it would only be for you to grow, not for the Outreachy process.

[marrious11]

Wow, @pitag-ha 🥲 I saw the release notes, they were awesome more than even what I thought it to be.

---

About Outreachy:
Yes, actually about contribution is over, I just wish to learn more and acquire software development skills in functional Programming with Ocaml. I believe that here in the community I will be able to learn as much as to prepare me to contribute professionally back to the community.

With the Ocaml community:

1. I believe to gain technical level experience in understanding of software engineering standard methodologies such as;

• Issues resolution

• Understanding large codebases

• code maintainability,

• code review, automated testing,

• continuous integration.

• and More...
  Please let me know if I can archive them here with the community!

[pitag-ha]

Hey @marrious11, I've just moved our conversation over to the issue dedicated to Outreachy-related things and have answered your questions there.