build: test with terraform v1.13

[isometry]

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[Copilot]

Pull Request Overview

This PR updates the testing infrastructure to use Terraform v1.13 and enhances Dependabot configuration with security-focused grouping. The primary purpose is to ensure compatibility testing with the latest Terraform version while improving dependency management.

• Updates Terraform version from 1.12.* to 1.13.* in CI workflows
• Adds Terraform v1.13.* to the test matrix for comprehensive version testing
• Configures Dependabot groups for golang, hashicorp, and github-actions dependencies with security update focus

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
.github/workflows/test.yml	Updates Terraform version to 1.13.* and adds it to test matrix
.github/dependabot.yml	Adds dependency grouping configuration for security updates and sets pull request limits

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