Add WattBuy API

[elianaschwartz]

Adding WattBuy API

• [x] My submission is formatted according to the guidelines in the contributing guide
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• [x] The description does not end with punctuation
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• [x] I have searched the repository for any relevant issues or pull requests
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[matheusfelipeog]

Hi @elianaschwartz

Thanks for your contribution ;)

We have some problems with Public APIs, so we won't be able to review/add this improvement right now.

Read this issue for more information, please: https://github.com/public-apis/public-apis/issues/3104

[marcelscruz]

Added on public-apis-dev/public-apis.