Remove set-output from Makefiles.

[bryanpaget]

I removed set-output from our Github Actions but we need to remove it from the Makefiles as well.

The following tickets have more information:

• set-output deprecation #493
• The set-output command is deprecated and will be disabled soon. #484

[bryanpaget]

If I have time, change set-output in other repos too or at least make a ticket for them.

[bryanpaget]

This has proven difficult in practice while in theory it's just a syntax update.

Failing:

• https://github.com/StatCan/aaw-kubeflow-containers/actions/runs/5860089373/job/15887482146

The above failing build boggles my mind since all I've done is change the following three lines:

And you'd think it would either work or not work but it seems to work for the rstudio image but not work for the other images.

[bryanpaget]

Update: I just noticed a missing $ on line 203. Rebuilding now.

[bryanpaget]

Blocked by #502