fix: organization prop contactPoint

[edoardolincetto]

Description of Change(s):

Fixes #925

As explained in the official schema.org docs:

contactPoints has been superseded.

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To help get PR's merged faster, the following is required:

• Updated the documentation
• Unit/Cypress test covering all cases

Please link to relevant Google Docs or schema.org docs for what you are adding so we can review.

Please have a read of the Contributing Guide for full details.

https://github.com/garmeeh/next-seo/blob/master/CONTRIBUTING.md

[garmeeh]

Thanks @edoardolincetto