Flux 2.9 release: new mirror and schema plugins

The Flux CLI now supports plugins and we have two official ones you can check out:

- Flux Mirror for syncing Helm charts, OCI artifacts and container images between registries. - Flux Schema for validating Kubernetes manifests against JSON schemas and CEL rules, offline from clusters.

These plugins should be useful to anyone working with OCI and Kubernetes. Notably flux-mirror uses a CNCF license which makes it a great replacement for bitnami/charts-syncer.

This release also adds:

- Field ignore rules that let server-side apply share ownership with other controllers. - Git commit signing and verification using SSH keys. - Kubernetes Workload Identity authentication for OpenBao/Vault and AWS CodeCommit. - Post-Quantum SOPS decryption for secrets using compatible age ciphers.

In the ecosystem, the Flux Operator v0.53.0 web UI has a new Workloads Dashboard and can view logs for Pods.