Summarize dependency track on current activities page

[marcelamelara]

#1268 added a dedicated "Current Activities" pages to better signal what the SLSA community is actively working on. This includes the Dependency track, but that section is currently a stub. It would be great to have a more detailed summary on that page.

Originally posted by @TomHennen in #1268 (comment)

[tombedfordgit]

I've created a pull request to add a bit more context about the current efforts for this track.

[tombedfordgit]

The changes were merged - thanks for the help