Fix misplaced module.exports in ES Modules build

[stefanmaric]

Hardcoded module.exports breaks webpack when importing the ES module build.

I've removed the add-module-exports plugin since it works only when the default export is the only export, which isn't the case for stream-tag.

Instead, I'm patching the commonjs build after the fact.

Related: https://github.com/webpack/webpack/issues/4039

[stefanmaric]

PD: please hide whitespace changes to review the diff; few files were in CRLF but the project's .editorconfig is configured with LF and my editor/prettier picked it up.