Add Bencher to Related actions

[epompeii]

Hey github-action-benchmark team, Thank you for creating and maintaining this GitHub Action! A couple of years ago, I needed to track performance in CI. Unfortunately, I was not able to use GitHub, and it needed to work on-prem. So I had to roll my own solution. This eventually grew to be a tool called Bencher.

The backend for Bencher is an open source API server with auth, so it can handle a couple of things that this action cannot, like safely benchmarking pull requests from forks, tracking multiple branches side-by-side, etc.

If you all would prefer to not merge this PR, I would totally understand. Thank you again for all the hard work. You all's test files have been super helpful for building out the benchmark harness adapters in Bencher. I have a shoutout to you all at the bottom of this section as a thank you!