Initial renovate configuration

Description

Initial stab at what updating the current layout for this template would look like for renovate configurations.

This can be used to help illustrate to consumers why they will want to monitor packages independent of the big bang version. Each package submits a separate MR - meaning users can merge updates to their gitops template separately and introduce updates incrementally.

Updates Included

This renovate configuration watches for:

• Big Bang release tags to update both base/kustomization.yaml and dev/kustomization.yaml
• Updates the individual packages for which have a mapping in the renovate.json to the declared file

Potentially out of scope

Open for discussion - the regex is quite strict with regards to the expected structure in the configmap.yaml for packages. Likely just needs some wizardry to match on everything between a initial key (IE package name) and the first instance of tag: but that comes with a lot of testing for edge cases.

OCI support is currently still under investigation - there is less documented support for how this would work outside of standard git-tag workflows. Need to determine how renovate would work for this before we make OCI the default.

I did not include updating any package information in this MR - I believe we should have another ticket that allows for both updating and testing for functionality/validity. This configuration merely ensures updates to the packages/umbrella are identified and submitted as issues/MR's as seen here

Issues

relates to big-bang/bigbang#1471 (closed)