fix: Updated apigee_envgroups variable type in hybrid-gke sample to match with referenced apigee module

[ronsonx]

Updated apigee_envgroups variable type in hybrid-gke sample to match with referenced apigee module

chore(main): release 0.13.0

What's changed, or what was fixed?

• Updated apigee_envgroups variable type in samples/hybrid-gke/variables.tf to match with apigee module: github.com/terraform-google-modules/cloud-foundation-fabric//modules/apigee?ref=v19.0.0.
• Updated sample value accordingly in samples/hybrid-gke/hybrid-demo.tfvars.
• Updated output variable apigee_envgroups in samples/hybrid-gke/outputs.tf to remove local reference.

Fixes: #issue

• [ x ] I have run all the tests locally and they all pass.
• [ x ] I have followed the relevant style guide for my changes.

[g-greatdevaks]

Hey @ronsonx, thanks for the PR. Can you please have this raised against the main branch instead?