Replace lit-element with Lit in integrations.md

[justinfagnani]

Lit is the current library name and lit.dev the current website.

Checklist:

• If this PR contains changes to the library itself (not necessary for e.g. docs updates), please include a changeset (see CONTRIBUTING.md)
• If this PR is a new feature, please reference an issue where a consensus about the design was reached (not necessary for small changes)
• Make sure all of the significant new logic is covered by tests

[apollo-cla]

@justinfagnani: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

[netlify]

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[changeset-bot]

⚠️ No Changeset found

Latest commit: 6f36e26

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[bignimbus]

Thanks @justinfagnani! 🚀