Add dataset index updating automation

[dotsdl]

Currently, the dataset index page is static and requires manual updates. As part of the STANDARDSv3 implementation, we would like this page's updates to be updated in an automated fashion so it functions as a useful indicator of dataset status for users.

This automation could take the form of a Github action that makes commits to master with changes to this file when it sees corresponding changes on QCArchive. The action could run regularly, but only make commits when the resulting file would actually be different.