Yarn workspaces check fails if there is no package.json at the project root.

[dreid]

We're not using yarn workspaces, instead we have a multi-language monorepo with our javascript code in a subdirectory. We use PT_PROJECT_ROOT to specify that subdirectory but because we do not have a package.json at the root of our repository this action fails with:

jq: error: Could not open file package.json: No such file or directory

Should PT_PROJECT_ROOT be handled before the yarn workspaces?