feat(pipelines): add IstioUpgrade step schema definition

[trevorwilliams2025]

What

• Adds istioUpgradeStep schema definition and if/then routing to pipeline.schema.v1.json so the pipeline framework can validate action: IstioUpgrade steps
• Changes aksCluster from type: string to $ref: "#/definitions/Value" to support configRef style
• Updates IstioUpgradeStep Go type to match: AKSCluster Value instead of AKSCluster string
• Removes dryRun field from both schema and Go type (no use case in pipeline context)

Why

Prerequisite for wiring the IstioUpgrade action into svc-pipeline.yaml, which will replace the legacy istio.sh shell script. The Go implementation is already merged in
ARO-HCP#5661.

[Copilot]

Pull request overview

Adds JSON Schema support for validating pipeline steps with action: IstioUpgrade by introducing a dedicated step definition and wiring it into the existing if/then action-dispatch logic. This extends the pipeline framework’s schema so future pipeline YAML updates can be validated without relying on legacy scripting.

Changes:

• Introduces a new istioUpgradeStep definition (with aksCluster required and optional dryRun).
• Adds if/then routing so steps with action: IstioUpgrade are validated against the new definition.

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[geoberle]

make this of type definition/Value so we can use `configRef``

i know that a lot of step allow for string params and then use gotmpl like
aksCluster: "{{ .mgmt.aks.name }}"

but instead we are heading towards

aksCluster:
   configRef: mgmt.aks.name

translates way better to EV2 and is a good preparation for future work that will adapt pipeline work.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

Comments suppressed due to low confidence (1)

pipelines/types/istio.go:32

• IstioUpgradeStep.AKSCluster is now a Value that can reference an input from another step, but RequiredInputs() always returns an empty list. This prevents the pipeline dependency graph from capturing input-chaining dependencies when aksCluster is populated via "input".

func (s *IstioUpgradeStep) RequiredInputs() []StepDependency {
	return []StepDependency{}
}

[trevorwilliams2025]

fixed.