v0.5.3

• Fix git checkout errors when using advanced git-based dependency swapping.

• When using dependency swapping, a fresh install will now be performed whenever
  any dependency version has changed (either in the original package.json, or
  in the dependency-swap configuration). The label field is no longer
  significant in this respect.

• When using advanced git-based dependency swapping {kind: 'git', ...}, a
  query will now always be made to the remote git repo to determine if the
  configured ref is still up to date. If it is stale, a fresh install will be
  performed.

• When using dependency swapping, temp directories will be deleted when there is
  an installation failure, so that they are not re-used in a broken state.