Test case for preactjs/prefresh#444
index.mjs imports @prefresh/babel-plugin, while index.js requires it.
After running yarn install, node index.mjs prints the imported function.
node index.js fails with an error:
Error: Cannot find module '/Users/eostrom/workspace/swagleft/prefresh-babel-require-test/node_modules/@prefresh/babel-plugin/dist/src/index.js'