chore: release 4.0.0

[release-please]

🤖 I have created a release *beep* *boop*

4.0.0 (2021-06-23)

⚠ BREAKING CHANGES

• target_name_server_addresses is now a list of objects, allowing setting forwarding_path for each address.
• add Terraform 0.13 constraint and module attribution (feat!: add Terraform 0.13 constraint and module attribution #22)

Features

• add force_destroy variable for zones (#29) (8bb8746)
• add Terraform 0.13 constraint and module attribution (#22) (52cd08a)
• allow setting routing path for target_name_server_addresses (#27) (53955cb)

Bug Fixes

• Remove deprecated list() function (#28) (7c9cd40)

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[comment-bot-dev]

Thanks for the PR! 🚀
✅ Lint checks have passed.

[bharathkkb]

/gcbrun

[morgante]

We need to fix tests and add an upgrade guide.

[keisku]

Any updates?

I would like to use this version.

[github-actions]

This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[bestefreund]

+1

[release-please]

🤖 Release is at https://github.com/terraform-google-modules/terraform-google-cloud-dns/releases/tag/v4.0.0 🌻