fix readme since we use singularized names.
fix readme since we use singularized names.

sunny2601/spree_taxon_filters,sunny2601/spree_taxon_filters,pero-ict-solutions/spree_taxon_filters,sunny2601/spree_taxon_filters,pero-ict-solutions/spree_taxon_filters,pero-ict-solutions/spree_taxon_filters