Unit tests are not run on PRs

[ipwnponies]

There exists unit test github action that is intended to run for all changes and pull requests:

pytest-antilru/.github/workflows/test.yaml

Lines 7 to 11 in 9e2eef7

	on:
	push:
	workflow_dispatch:
	schedule:
	- cron: '0 2 * * SAT'

This isn't working as expected for #35.

Staring at the docs harder:

For pull requests from a forked repository to the base repository, GitHub sends the pull_request, issue_comment, pull_request_review_comment, pull_request_review, and pull_request_target events to the base repository. No pull request events occur on the forked repository.

For the unit test, we want pull_request to trigger a run. We use default types, which map to "run when there are new commits":

By default, a workflow only runs when a pull_request event's activity type is opened, synchronize, or reopened.