Ark: Modernize GHA workflows and remove warnings

[DavisVaughan]

• mukunku/[email protected] could be upgraded to 1.6.0

• actions/create-release@v1 was long since deprecated, and could be replaced with softprops/action-gh-release@v2 with a little bit of extra effort, we have been using this on Positron builds today

• actions/upload-release-asset@v1 also deprecated, and also can be replaced with softprops/action-gh-release@v2 as it allows files to be specified as additional assets even if a release already exists, and we use this on Positron builds today

• Upstream r-lib/actions needs to drop usage of save-always Remove save-always usage r-lib/actions#934. We will get that for free when they do

To see all the warnings look at the Annotations under a release workflow like https://github.com/posit-dev/ark/actions/runs/11036546624

Notably GitHub is going to force node 20 very soon, so we should prioritize this

[lionel-]

Looks like our slack report job is broken, should also update it: https://github.com/posit-dev/ark/actions/runs/11054417985/job/30711190350?pr=546

Most likely because secrets are disabled in pull requests: bitrise-steplib/steps-slack-message#67

[DavisVaughan]

✅ posit-dev/ark#600