Fix build failure for course notes

[andrewgait]

What do you want us to do?

The course notes are currently failing to build (in the scheduled workflow), see e.g. https://github.com/UoMResearchIT/Software-Development-With-Python/actions/runs/32792926981

I’m not quite sure why but I’m wondering whether it might be because the default branch is development rather than main?

(The same is true for the other new set of course notes as well).

[douglowe]

Looks like some packages aren't installing properly - even though they do look to be downloaded.

The following package(s) were not installed successfully:
- [base64enc]: install failed
- [rlang]: install failed
- [yaml]: install failed

base64enc 0.1-3
rlang 1.1.5
yaml 2.3.10

[douglowe]

I wonder if we shouldn't include the renv directory - see this repo for example setup: https://github.com/carpentries-incubator/python-intermediate-development

[andrewgait]

I wonder if we shouldn't include the renv directory - see this repo for example setup: https://github.com/carpentries-incubator/python-intermediate-development

Looks like that repo uses a different (set of) workflow(s) for building the course notes which are more recent than the ones we are using. It's probably worth updating our workflows to match.

I think it is also the case that these workflows only work on the main branch so it's probably also worth changing to use main as default on our repositories too.