v0.4.3: Source TIND metadata from the API

• Switches from the public search endpoint to the authenticated /api/v1/search endpoint, bypassing newly added TIND restrictions on non-human clients.
• Consumers will need to set LIT_TIND_API_KEY in their environment to authenticate requests.

What's Changed

• Ap 483 by @jason-raitz in #4

Full Changelog: 0.4.2...0.4.3