Remove main field indication

Author: martpie

README.md

@@ -99,7 +99,7 @@ module.exports = withTM({
 **Notes:**
 
 - please declare `withTM` as your last plugin (the "most nested" one).
-- make sure all your packages have [a valid `main` field](https://docs.npmjs.com/cli/v6/configuring-npm/package-json#main).
+- ~~make sure all your packages have [a valid `main` field](https://docs.npmjs.com/cli/v6/configuring-npm/package-json#main).~~ (not needed anymore since `7.1.0`)
 - there is currently no way to transpile only parts of a package, it's all or nothing
 
 ### Scoped packages