Add tox and GitHub Actions

[eumiro]

Add tox and GitHub Actions (along with Python 3.8 and 3.9). Since this repository still does not use GHA in its main branch, the badge won't be shown immediately, but the CI results can be seen in my branch.

[eumiro]

Oh yes, it looks like it has worked: https://github.com/eumiro/destream/runs/1674539754

[cecton]

Do you want to join the owners/maintainers? It would help reduce the bus factor (I'm here temporarily)

[eumiro]

Do you want to join the owners/maintainers? It would help reduce the bus factor (I'm here temporarily)

I came because EuroPython retweeted your request and saw there's work to be done. You can add me to the list.

[cecton]

@eumiro it's weird that we don't see the checks running on this PR. We should see them. I think you might have something messed up with the triggers.

I usually use this:

on:
  pull_request:
    branches: [main]
  push:
    branches: [main]
  schedule:
    - cron: 0 0 1 * *

So it builds:

• when there is a pull request against the branch main
• when there is a push on the branch main
• once every month (to make sure it is stable)

[eumiro]

I'll change it to what you proposed (actually wanted to add that cron entry to my projects as well), but this won't help anyway, because I believe that if .github/workflows is not in the upstream repository, it won't be shown. And this is the very first PR introducing the CI.

And my current proposal is just more general, because it triggers at any push/PR and not only against the main branch.

[eumiro]

Now I'll need a review approval and we can go on.