fix: add default value for browserslist config path

[JLHwung]

Q	A
Fixed Issues?	Fixes recent CI vue e2e error (hopefully). Closes #13154
Patch: Bug Fix?	Y
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

Thanks to investigations from @sodatea (#13154 (comment)), the vue-cli e2e error caught a regression introduced in #12189. When we switched from browserslist to browserslist.loadConfig, we should add default value for configPath like browserslist did here: https://github.com/browserslist/browserslist/blob/98d5352e06/index.js#L406-L408

I have added new tests on unspecified configPath.

Disclaimer: I didn't run vue-cli e2e tests, let's see if CI can be green.

[JLHwung]

Unlike browserslist, we use "." instead of path.resolve(".") here to avoid import "path" so we don't have to add a packageJson.browsers field for this package.

browserslist will use path.resolve when it is running in a Node environment:

https://github.com/browserslist/browserslist/blob/209adf9e0051fa39a2b25354cffd493300f34b02/node.js#L302

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/45227/

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[hzoo]

thanks @sodatea and @JLHwung!

[sodatea]

Thanks for the fix.
Do you have any planned release date that I can expect for this fix to be landed?
I'm not sure if I need to work around this issue in Vue CLI, too, if I'm gonna release a new version before the Babel patch.

[nicolo-ribaudo]

There have been a few fixes on main, I can release now.

[sodatea]

Thank you so much!