CI: Update wpilibsuite signing action for macOS

[shinra-electric]

This updates the import signing certificate to the latest version. It should silence several warnings in the actions builds.

Since this is security related, it needs to be thoroughly reviewed.

I noticed that the wpilibsuite repo does not get updated very often, sometimes years between commits. Since this is security related, it might be an idea to switch to an alternative tool that's updated more often. There are a few options including Apple Actions which looks like it's kept up to date on a regular basis.