Autoplot v2024a_8 released

[Jeremy Faden CS]

I've made a new release of Autoplot.  I finally figured out what I was
doing wrong when signing the Mac DMG release, so please give that a try
now and let me know if you have any issues.

This has a number of changes to highlite:

* CDF files made in SpacePy on a Mac with ARM processor are now supported.
* corrections to scan/step logic, where sometimes "scan" appeared when
"step" should have been.
* Series mode respects cadence property.
* Corrections to code which keeps track of the GUI margins.

and new features like:

* PDS3/PDS4 metadata from Label file is shown in the metadata tab
* String completions when string starts with "https://"

See https://autoplot.org/latest/, and thanks for all the feedback!

Jeremy