Check EOL dates automatically

[eloquence]

EOL dates can be manually configured, or retrieved from endoflife.date's API. See eol.yaml.sample in this branch for an example.

As a nightly job: Using the token configured in https://github.com/freedomofpress/infrastructure/issues/5824, opens issues. Using write permission, commits an ICS calendar file to the main branch in this repo.

Resolves #23

Background

Ready for initial review - commits & issue creation should work once we configure the tokens. We'll need an ISSUES_TOKEN with access to any repos we want to be able to open issues in, and a PUSH_TOKEN with access to this repo.

Code written & co-generated with ChatGPT o3 and Claude Code. Example GitHub action run for generate-ics: https://github.com/freedomofpress/securedrop-dev/actions/runs/15887471512/job/44802858613

I've tested issue creation (including no duplication of existing issues) against a private repo. I've also tested calendar import via GCal.

[legoktm]

Just did a quick code review (didn't try it out), overall looks good! Did you already try loading an ICS from GitHub with Google Calendar? Or did you have some other integration/hosting in mind?

[eloquence]

Thanks @legoktm, I think I addressed your comments. I did previously successfully import the generated ICS file into GCal.

Thanks for pointing out that we don't need a push token! I've requested the ISSUES_TOKEN over in https://github.com/freedomofpress/infrastructure/issues/5824. Once we have that I think we can take this for a spin. We can keep the fedora-40 in for now to see if it'll successfully open an issue for that.

[eloquence]

Thanks @legoktm, this should be ready for another pass. I've tested issue creation (freedomofpress/securedrop-workstation#1364); on running the job a second time, it also correctly detected an existing (closed) issue and did not re-create it. I've removed that Fedora 40 check now, since it doesn't tell us anything new, so it'll be a while til the issue creation job is expected to fire.

[legoktm]

LGTM, thanks! :)