Sync with [dvc-objects v0.1.7](https://github.com/iterative/dvc-objects/releases/tag/0.1.7).
0.1.11
What's Changed * state: don't forget get_unused_links/remove_links by efiop in https://github.com/iterative/dvc-data/pull/120 * db: local: get rid of redundant unused cache_dir/path by efiop in https://github.com/iterative/dvc-data/pull/121
What's Changed * dvc_data: introduce basic data index by efiop in https://github.com/iterative/dvc-data/pull/115 * dvc-data: add DataFileSystem by efiop in https://github.com/iterative/dvc-data/pull/116