Revert "feat: package is now ESM (#716)"

This reverts commit 6c5bafb.

Author: wolfy1339

.github/workflows/update.yml

@@ -18,7 +18,7 @@ jobs:
           token: ${{ secrets.OCTOKITBOT_PAT }}
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version: 16
           cache: npm
       - run: git checkout routes-update || true
       - run: npm install @octokit/types@latest

README.md

@@ -30,8 +30,10 @@ Node
 Install with `npm install @octokit/core @octokit/plugin-rest-endpoint-methods`. Optionally replace `@octokit/core` with a compatible module
 
 ```js
-import { Octokit } from "@octokit/core";
-import { restEndpointMethods } from "@octokit/plugin-rest-endpoint-methods";
+const { Octokit } = require("@octokit/core");
+const {
+  restEndpointMethods,
+} = require("@octokit/plugin-rest-endpoint-methods");
 ```
 
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