Update module name for Costar

[JordanMartinez]

Description of the change

Part of https://github.com/purescript/purescript-profunctor/issues/23

Consequence of purescript/purescript-profunctor#41 and purescript/purescript-functors#31.

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Checklist:

• [ ] Added the change to the changelog's "Unreleased" section with a link to this PR and your username
• [ ] Linked any existing issues or proposals that this pull request should close
• [ ] Updated or added relevant documentation in the README and/or documentation directory
• [ ] Added a test for the contribution (if applicable)