build(deps): group Dependabot minor/patch updates into weekly PRs

[kperry-godaddy]

.github/dependabot.yml currently has no groups configuration for either ecosystem (gradle, github-actions), so every dependency bump arrives as its own PR.

Add grouping following the model merged in the ans repo (agentnameservice/ans#70): minor and patch bumps arrive as one consolidated PR per ecosystem per weekly run, while major version updates intentionally remain individual PRs so breaking changes get isolated review.

Suggested config, mirroring ans:

version: 2
updates:
  - package-ecosystem: "gradle"
    directory: "/"
    schedule:
      interval: "weekly"
    open-pull-requests-limit: 5
    groups:
      gradle-minor-patch:
        patterns:
          - "*"
        update-types:
          - "minor"
          - "patch"
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "weekly"
    open-pull-requests-limit: 5
    groups:
      actions-minor-patch:
        patterns:
          - "*"
        update-types:
          - "minor"
          - "patch"

Note: on the first run after merge, Dependabot will close any currently open per-dependency PRs and re-open them as grouped PRs.