@uppy/transloadit: pass fields to transloadit

[aduh95]

Co-authored-by: Merlijn Vos Murderlon@users.noreply.github.com
Fixes: #3189

[Murderlon]

If the E2E tests works correctly then we can merge

[aduh95]

If the E2E tests works correctly then we can merge

It doesn't though, and I don't know if we should block the landing at this point as I don't know how to make them work.

[aduh95]

The clue I have is this is skipping the test:

uppy/test/endtoend/transloadit2/test.js

Lines 18 to 22 in b364708

	const transloaditKey = process.env.TRANSLOADIT_KEY
	if (transloaditKey === undefined) {
	console.log('skipping Transloadit integration test')
	return this.skip()
	}

If someone knows if and why TRANSLOADIT_KEY is not defined, and how to fix it, I'm happy to work on it, but otherwise we can leave it to a future PR to fix this test suite.