Decide re divergence between our repository and Microsoft's

[mattmccutchen-cci]

Our plan is to periodically send PRs of our entire repository to Microsoft. However, there are some files that GitHub recognizes only in the default branch of our repository that we might want to be different in our repository and would need to avoid sending to Microsoft:

• The root README.md, which is the first thing most people will see if they open our repository as such and thus may be important for branding, though the planned link from https://correctcomputation.com could deep-link to a 3C readme elsewhere in the tree.
• .github/workflows/main.yml, which defines our GitHub actions (which Microsoft shouldn't run). For now, since we have only scheduled actions, a workaround would be to move them to a different repository and they could still read from this repository. But in the future, if we want to trigger an action on pull requests to this repository, we'd have to deploy our own process that detects the pull request and triggers the action rather than using GitHub's built-in functionality to trigger an action on a pull request to the same repository.
• In the future, possibly other GitHub configuration files such as CONTRIBUTING.md and issue templates.

Over the past few weeks, we've debated whether to (a) adopt a workflow that maintains differences in these files between us and Microsoft at the cost of some complexity or (b) forego modifying the files for now, using workarounds where we can and giving up functionality where we can't. (More here.) Currently, we're leaning toward (a) with method 2 from that document.

[mattmccutchen-cci]

New plan:

• For the Microsoft PR and publicity within Microsoft, move the action file to another repository and leave the root readme unchanged (they will look at our other readmes). The action file move is underway; when it is confirmed to be successful, this issue will be removed from that GitHub project and left open for the next step.
• For external publicity, adopt a divergence solution and then modify the root readme.

[mattmccutchen-cci]

For the first step, the divergence has been resolved for now (to our knowledge: something else might come up during review of #314) with the deletion of the actions file in #318.