Yarn.lock should not be a registered filename in yaml language contributes

[JPinkney]

Currently yarn.lock is registered as a filename in the yaml language contributes but yarn.lock is not actually valid yaml. Our extension (https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml) provides support for yaml files but is being activated on yarn.lock files despite yarn.lock not being actual yaml.

As far as I can see there is no way to override vscode's language contributes so I request that this line is removed.