feat: add renovate config

[calebhansard]

What does this PR do?

This PR adds a renovate.json config file to automatically create PRs using Renovate for Helm chart version updates in main.tf.

The regex used in the config to match the chart versions can be validated here: https://regex101.com/r/MB6rrh/2

To make use of this config, install the Renovate Cloud-Hosted App on your GitHub org, then select the repos to enable.

Motivation

• Resolves [CI] - Improve Version Management  #50

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I ran pre-commit run -a with this PR

For Moderators

• E2E Test successfully complete before merge?

Additional Notes

The renovate config is setup to only use the regex manager. Other managers such as terraform can optionally be enabled to automatically create PRs for terraform module and provider updates.

Example pull requests created by Renovate for this project can be found here: https://github.com/calebhansard/terraform-aws-eks-blueprints-addons/pulls