feat: export ErrorWrapper

[phegman]

Export ErrorWrapper so it can be used when extending VTU.

At GitLab we have an extendedWrapper helper that we use to add custom finders and matchers. We are trying to add some DOM testing library finders to our extendedWrapper but one problem we are running into is ErrorWrapper is not exported so we have to do something like this. Ideally we would be able to do return new ErrorWrapper(query).

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the dev branch.
• [-] When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• All tests are passing: https://github.com/vuejs/vue-test-utils/blob/dev/.github/CONTRIBUTING.md#development-setup
• New/updated tests are included

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:

[phegman]

Question: should dev/packages/test-utils/types/index.d.ts be updated for a change like this? Is there a way to generate typescript definitions, or are these manually maintained?

[lmiller1990]

Hi! The types are manually maintained (not exactly ideal). You can update them if you like. If you want to, let me know when you want to merge. If not, I can merge this now and prepare a release soon.

[phegman]

@lmiller1990 thanks for the reply! I'm good with merging this as is. I'd be happy to help with the TypeScript definition later down the road if there is demand for it 🙂

[lmiller1990]

I will do a release this week.

[phegman]

Thanks so much!