feat: yarn version berry workspace autocompletion

[devthejo]

Hello @dsifford ,
first I want to thank you for this great autocompletion script,
I use yarn berry version (v2/v3) and the completion work for most of commands except for yarn workspace, this PR solve this, detecting yarn v2/v3 and use correct completion command for workspaces adressing this issue and makin my life easier ;):
#49

[dsifford]

Thanks for the contribution! This looks pretty good, except that it will not work under certain circumstances. See comments for explanation.

[dsifford]

This will only work properly if you are completing yarn from the root of the project. If you call yarn workspace <Tab> from any child directories, this will fail.

See the following snippet for how the script locates the package.json file.

yarn-completion/yarn-completion.bash

Lines 35 to 41 in 73fe678

	while [[ -n $cwd ]]; do
	if [[ -f "$cwd/package.json" ]]; then
	package_dot_json="$cwd/package.json"
	break
	fi
	cwd="${cwd%/*}"
	done