ignore babelrc in git-upgrade

[ngraef]

Per this comment on the issue:

Babel by default tries to find .babelrc files to configure itself, and once it finds the one from the RN app (which links to the RN preset that only works on Babel 7) it fails.
The easiest patch to fix this issue is to add babelrc: false to the babel-register method, so Babel does not read any additional .babelrc file.

Fixes #20710

Test Plan:

$ react-native init TestUpgrade
$ cd TestUpgrade
$ react-native-git-upgrade next

Output from react-native-git-upgrade:

git-upgrade info Generate new version template 
git-upgrade info Add updated files to commit 
git-upgrade info Commit new version template 
git-upgrade info Generate the patch between the 2 versions 
git-upgrade info Save the patch in temp directory 
git-upgrade info Reset the 2 temporary commits 
git-upgrade info Apply the patch 
git-upgrade info Upgrade done

Release Notes:

[INTERNAL] [BUGFIX] [react-native-git-upgrade/cli.js] - Prevent react-native-git-upgrade from using project's Babel 7 .babelrc

[facebook-github-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file. In order for us to review and merge your code, please sign up at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need the corporate CLA signed.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[ngraef]

@facebook-github-bot CLA signed

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Facebook open source project. Thanks!

[kelset]

👋 thanks for submitting!
I'll try to get this merged asap :)

[facebook-github-bot]

hramos is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[ngraef]

I originally marked this as [INTERNAL], but I'm now realizing this will require a new version of react-native-git-upgrade because it doesn't delegate to the local package like react-native-cli does, right? If that's the case, this should probably have some release note visibility.

[hramos]

I've edited the imported diff to use CLI instead of INTERNAL in the release notes.

[react-native-bot]

This pull request was closed by @ngraef in b4a8630.

Once this commit is added to a release, you will see the corresponding version tag below the description at b4a8630. If the commit has a single master tag, it is not yet part of a release.