Fix the failing installation of bundler in the publish step.

[hodgestar]

Description

Doing sudo gem install bundler used to work, but a recent update to Ubuntu images in the GitHub action works seems to have broken then. A previous attempt to install bundler locally in #42 cause the bundler executable to not be on the path. This PR aims to sort everything out.

Update: The issue was caused by an update to bundler 2.4.x. Before 2.4.x, bundler would automatically run sudo to upgrade its permissions (wat). The behaviour from 2.4.x onwards is much more sane (i.e. it doesn't sudo itself) but it means the gem install path needs to be given explicitly.

Tried so far:

• Try run jekyll without bundler since we have no GemSpec to install (does not work because we need to install our gems from our GemFile -- doh).
• Set the bundle install path (works).

Related

• 42

[hodgestar]

Pleasure! That was a bit of a bizarre bug to track down.