Switch to upstream Zola

[senekor]

All of the patches we needed for the migration have been merged upstream (with some modifications, hence the sort_by = "permalink" diff).

We don't know how long it will take for Zola to cut a new release, so let's provide our own binaries to blog authors in the meantime.

Rendered

[senekor]

I tried and failed to run the snapshot tests in CI. The reason is that only one version of zola is installed for both the "before" and "after" builds of the site. However, the new version of zola we're using relies on the sort_by = "permalink" lines, otherwise the order of posts is messed up. At the same time, the old version of Zola cannot be used either, because it errors out on the unknown value "permalink" for the sort_by key.

However, I did run the tests locally:

1. Install old version of zola
2. Build "before" snapshots on master branch
3. Install new version of zola
4. Test snapshots on the PR branch

The tests passed, so I'm confident there is no impact on the site.

[senekor]

Maybe worth mentioning: If this is merged, people who currently have my fork of zola installed will run into build errors (due to the unknown "permalink" value). The solution is to install the new version. I don't expect this to happen when Zola has an official release and we can switch to using those binaries, they should be compatible.

[rustbot]

⚠️ Warning ⚠️

• Some commits in this PR modify submodules.