Manage GCP SDKs version with Dependabot

[zmoog]

Proposed commit message

Set up Dependabot to manage the GCP SDK version.

With the current reactive and manual process, our dependencies are often outdated. To release a bugfix to a dependency, we need to wait for the following stack release instead of merging it shortly after it's available from GCP.

See #39492 to learn more.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Related issues

• Relates Keep the AWS/Azure/GCP SDK version up to date #39492

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @zmoog? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[zmoog]

Hey @gpop63, cloud.google.com/go/* seems to be the main package for the GCP SDK. Are there other GCP packages we should consider managing with Dependabot?

[gpop63]

Hey @gpop63, cloud.google.com/go/* seems to be the main package for the GCP SDK. Are there other GCP packages we should consider managing with Dependabot?

Hmm, maybe also google.golang.org/*?

[elasticmachine]

Pinging @elastic/obs-ds-hosted-services (Team:obs-ds-hosted-services)