fix: prevent yarn directory traversal on plugin installation

[techchrism]

fixes #4041 (and possibly others)

Yarn would previously traverse up the directory tree looking for a workspace package.json.
This PR prevents this behavior by writing a dummy package.json so yarn stops looking.

Solves errors that occur when a package.json exists in a parent directory (such as the user home directory or the root directory). Even when those errors don't occur, this may speed up execution very slightly by making fewer disk calls.

[CLAassistant]

All committers have signed the CLA.

[techchrism]

@gatzjames any reason in particular this was closed?
I still have people reporting an inability to install my plugin because of the underlying issue this PR fixes.
For another recent example from a repo that isn't mine, see jreyesr/insomnia-plugin-batch-requests#17

[gatzjames]

Thanks for the PR!
We were doing some cleanup and this was closed because the issue it references seemed to be resolved.