Bump required swh-storage version.

requirements-swh.txt

 swh.core >= 0.0.57
 swh.model >= 0.0.32
-swh.storage >= 0.0.137
+swh.storage >= 0.0.140
 swh.vault >= 0.0.23
 swh.indexer >= 0.0.120
 swh.scheduler >= 0.0.31