Node version warning

[phillip-haydon]

This action works perfectly, but it looks like it has a warning now for node version, even tho there's nothing preventing it from working in newer/older versions.

https://github.com/mmoyaferrer/set-github-variable/blob/main/action.yml

This looks like it specifies node12.

https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/

Looks like the recommendation is 20, would you be able to update this to remove the warning.