change: resolve fetch text to response.data

[saibotsivad]

Proposed solution for #40

I've been rolling with this version a bit and it seems correct so far.

[lukeed]

It’s only correct for non binary data. For example, it’ll break when fetching an image asset.

This needs a full body detector, like in worktop, or to expose the raw response (consistently), since here you do get the response for your text-based response and can call .text() yourself

[saibotsivad]

Ah yeah, I see what you mean. In the Node version the concat works even on binary data. I'll close this PR then.