Release v1.29.0/v0.123.0

[github-actions]

Like #4522, but for v1.29.0/v0.123.0
Performed by collector release manager

• Prepare core release v1.29.0/v0.123.0
• Tag and release core v1.29.0/v0.123.0
• Prepare contrib release v0.123.0
• Tag and release contrib v0.123.0
• Prepare otelcol-releases v0.123.0
• Release binaries and container images v0.123.0

Performed by operator maintainers

• Release the operator v0.123.0 opentelemetry-operator#3865

Performed by helm chart maintainers

• Update the opentelemetry-collector helm chart to use v0.123.0 opentelemetry-helm-charts#1602

[codeboten]

This is now complete