#237, #243 & #233 updated the peer dependencies of our models to be core and converter instead of the union.

However since the rollup config was not updated, this resulted in published model's bundles to include the whole tfjs-core and tfjs-converter. E.g. https://unpkg.com/@tensorflow-models/coco-ssd@1.1.0/dist/coco-ssd.min.js is ~577KB but should be ~27KB.

After this change, I will re-release patch versions of the updated models.