Clean up old branches

[dlongley]

There are some old branches (years!) named update-deps* and so on. We need someone in the know to clean this repo up.

[aljones15]

Upgrade Karma 6 is being used by another project: https://github.com/digitalbazaar/bedrock-karma/tree/upgrade-karma-6

The major issue for no PR with this, is that I couldn't replicate the previous reporter functionality one to one, we had to use a newer code coverage plugin with RegExps and such and it didn't work as well as the previous code coverage tool which didn't work with karma 6. Then karma's own code coverage tool had issues which I wasn't able to solve due to time constraints.