chore: Update CI with new actions and change renovate schedule

[jimmycallin]

• I have added automatic tests where applicable
• The PR title is suitable as a release note
• The PR contains a description of what has been changed
• The description contains manual test instructions

Changes

• The Renovate schedule was a bit too noisy, so changing it to running once every 3 months. It should be often enough to keep the library up to date, while rare enough to not become a chore.
• Added new CI steps.

Test

Make sure CI is green.

[gismya]

I agree with the noise issue. Especially in this repository, where (At least to me) testing if anything breaks is a hassle. But my vote would be on seeing if once a month would work. I could even take the opportunity to take a more active role in the approval pipeline for renovate.

[jimmycallin]

it is done!