Update @octokit dependencies, which are now ESM packages

This is going to require even more contortions around using `import` to pull in the packages, which is horrible, but here we are.

Locate the @octokit dependency declarations and the code that imports or uses those packages. Start by checking how the current imports are loaded, then run the existing test suite after updating them; done means the dependencies use their ESM-compatible imports and the tests still pass.

Written by the indexing model from the issue text.