feat: @octokit-next/core (#81)

README.md

@@ -54,10 +54,26 @@ A list of breaking changes compared to latest `@octokit/*` modules
   const result = await request("GET /", { request: { fetch } });
   ```
 
+- `Octokit.defaults` is now `Octokit.withDefaults`
+
+- `Octokit.plugin` is now `Octokit.withPlugins`. Instead of accepting one argument per plugin, the method now accepts a single array argument with all plugins to be applied.
+
 - `@octokit/openapi-types` will be renamed to `@octokit/types-openapi` to be consistents with the `@octokit/types-*` prefixed packages that only contain types
 
 - `@octokit/auth-token`: `createTokenAuth()` no longer accepts a `token` string argument, but requires `options.token`.
 
+- plugins now receive all options passed to the `Octokit` constructor as well as its defaults. Previously only the options passed to the constructor were passed
+
+## Features
+
+- `Octokit.DEFAULTS`
+- `octokit.options`
+
+## Notes for later
+
+- replace `request.defaults()` and `endpoint.defaults()` with `request.withDefaults()` and `endpoint.withDefaults()`
+- remove `options.previews` from `new Octokit(options)`
+
 ## Known issues
 
 - Constructor option Types (`options.auth`) are not set correctly when `authStrategy` is set via `.withDefaults({ authStrategy })` ([#20](https://github.com/octokit/octokit-next.js/issues/20))