coqbot should track uses of the minimizer itself

[JasonGross]

Probably by commenting on coq-community/run-coq-bug-minimizer#8, or editing a comment there, with some log of uses.

Possible data that's useful to track:

• PRs that minimization was possible on
• PRs that minimization was triggered on
• Duration, time, trigerrer, and stats about minimization for each minimization run, and any emoji reactions to that run

[JasonGross]

Thoughts:
We could include in the "I've started minimization" comment a unique identifier and other debug information (including #130, how the minimization was triggered, by whom, etc), all hidden by code folding. Then when posting the final comment, the minimizer could use this unique identifier to fetch the relevant debug info, and also post a comment to coq-community/run-coq-bug-minimizer#8 with the relevant info (we should be careful not to tag anyone on that thread, though) (new comment rather than edit comment to avoid github comment length limits and to avoid race conditions).

[JasonGross]

Alternatively, we could just make text files in, e.g., a logging branch of run-coq-bug-minimizer (perhaps making a folder for each PR and for each UID and for each ci target) (name of text file could be current-time---random-sequence.txt)

[JasonGross]

Possibly use GraphQL API for adding files