adds pact broker renovate dep updates

[ChrisJBurns]

🔧 Configure Renovate for Pact Broker Docker Image Updates

Summary

Adds custom Renovate configuration to properly detect and update Pact
Broker Docker image versions that use a non-standard versioning scheme.

Problem

The Pact Broker Docker image uses a custom versioning format:
M.m.p-pactbroker<version> (e.g., 2.124.0-pactbroker2.112.0). Standard
Renovate configuration doesn't understand this format, preventing
automatic dependency updates.

Solution

Enhanced renovate.json with:

• Custom regex versioning to parse the M.m.p-pactbroker format
• Regex manager to detect version updates in
  charts/pact-broker/values.yaml
• Package rules to apply the custom versioning to the Pact Broker Docker
  image

Versioning Scheme Details

The Docker image follows this pattern:

• Major (M): Breaking changes, major Pact Broker gem updates, incompatible base image changes
• Minor (m): New non-breaking features, minor Pact Broker gem updates
• Patch (p): Bug fixes, patch Pact Broker gem updates
• Suffix (-pactbroker): Informational, indicates the Pact Broker
  gem version

Impact

Renovate will now:

1. Correctly parse Pact Broker Docker image versions
2. Create PRs for new image releases following semantic versioning rules
3. Maintain the special versioning format in values.yaml

Related

• Pact Broker Docker Hub:
  https://hub.docker.com/r/pactfoundation/pact-broker
• Previous versioning scheme (deprecated May 2023): M.m.p.RELEASE