browserslist extends clause not supported

[sventschui]

Putting an extends my-node-module inside browserslist in package.json crashes wmr with the following error:

Error: Dynamic requires are not currently supported by @rollup/plugin-commonjs

[developit]

Seems like browserslist must be doing a dynamic require() to get the extends value. I think we should be able to allow-list it somehow here: https://github.com/preactjs/wmr/blob/99e56d782621a25e292977a74cff662ab5561c94/rollup.config.js#L131