GitLab

.gitlab-ci.yml:  Try out separate caches for each piece, since they don't appear to really share any usable artifacts

src/model.rs:  Item:  Make icon and flavor_text optional; allow listing_count to have a default value of 0

src:  Change Client to store league, passed into Client::new(); use that in the lower-level getters, rather than passing it in from the high-level getters