docs: Add Google Cloud Terraform repository

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Hi Dify Team,

We have developed a Terraform configuration repository for deploying Dify on Google Cloud. While the Dify repository's README currently includes Terraform configurations for Azure, it does not yet have one for Google Cloud.

Would it be possible for me to create a pull request to add our Google Cloud configuration repository to the Dify README?

Thank you for your consideration.

https://github.com/DeNA/dify-google-cloud-terraform