website: Update Hugo to latest version

[akronb]

I can't run local build because the site is incompatible with the latest version of hugo that I installed via brew (unfortunately, brew has disabled the ability to install older versions of applications).

I ended up installing hugo v0.76.5 from tarball. It is possible, but requires extra time to look into the issue. That is why I propose to try to update the site to the latest version of hugo or write instructions on how to install it correctly.

Also, README states that the "canonical" version of hugo is specified in travis.yml, but this file is not in the repository.

[hellais]

Yes I agree we should update the site to the latest version of hugo. The last time I tried using the latest version I seem to recall that there were some issues with it, but I don't remember the details.

We have since switched to github actions and netlify, but haven't updated the Readme to reflect that. The versions we pin hugo to are defined in here:

• https://github.com/ooni/ooni.org/blob/master/netlify.toml#L6
• https://github.com/ooni/ooni.org/blob/master/.github/workflows/main.yml#L21

[hellais]

We have now upgraded to 0.111.3: https://github.com/ooni/ooni.org/commit/0cab823a804e6305cba3c020799544700942ecaf