Add bigtable GCPolicy resource

[rileykarson]

Upstreams hashicorp/terraform-provider-google#3293

I want to amend the sidebar as part of this PR, so I'll add a depends: on the downstream, merge it, and then generate downstreams again.

Release Note Template for Downstream PRs (will be copied)

`google_bigtable_gc_policy`

[modular-magician]

Hi! I'm the modular magician, I work on Magic Modules.
I see that this PR has already had some downstream PRs generated. Any open downstreams are already updated to your most recent commit, df10890.

Pull request statuses

No diff detected in terraform-google-conversion.
No diff detected in Ansible.

New Pull Requests

I built this PR into one or more new PRs on other repositories, and when those are closed, this PR will also be merged and closed.
depends: hashicorp/terraform-provider-google-beta#1212
depends: hashicorp/terraform-provider-google#4578
depends: modular-magician/inspec-gcp#213

[modular-magician]

Hi! I'm the modular magician, I work on Magic Modules.
I see that this PR has already had some downstream PRs generated. Any open downstreams are already updated to your most recent commit, b41a749.

Pull request statuses

No diff detected in terraform-provider-google-beta.
No diff detected in terraform-google-conversion.
terraform-provider-google already has an open PR.

New Pull Requests

I built this PR into one or more new PRs on other repositories, and when those are closed, this PR will also be merged and closed.
depends: ansible-collections/google.cloud#15
depends: modular-magician/inspec-gcp#214

[rambleraptor]

It looks like the Magician switched downstreams?

[modular-magician]

Hi! I'm the modular magician, I work on Magic Modules.
I see that this PR has already had some downstream PRs generated. Any open downstreams are already updated to your most recent commit, df10890.

Pull request statuses

No diff detected in terraform-google-conversion.
terraform-provider-google already has an open PR.
No diff detected in Ansible.
InSpec already has an open PR.

New Pull Requests

I built this PR into one or more new PRs on other repositories, and when those are closed, this PR will also be merged and closed.
depends: hashicorp/terraform-provider-google-beta#1213

[rileykarson]

@slevenick I tried to do something clever by merging the downstream first, but it didn't end up working out. Only tpg/tpgb have real downstreams I think, and the code-generation failure is outdated.