feat: add SnapshotVariables for releases and runbook snapshots

[justin-newman]

Summary

Adds two package-level client functions that refresh ("re-snapshot") the variable snapshot on an existing release or runbook snapshot, by POSTing to the server's snapshot-variables endpoints:

• releases.SnapshotVariables(client, spaceID, releaseID) (*Release, error) → POST /api/{spaceId}/releases/{releaseId}/snapshot-variables
• runbooks.SnapshotVariables(client, spaceID, snapshotID) (*RunbookSnapshot, error) → POST /api/{spaceId}/runbookSnapshots/{snapshotId}/snapshot-variables

Both follow the existing package conventions: validate parameters, expand a uritemplates template, and call newclient.Post. Each mirrors its neighbouring function's validation-error style — releases.SnapshotVariables uses CreateInvalidParameterError (like GetReleaseDeploymentTemplate); runbooks.SnapshotVariables uses CreateRequiredParameterIsEmptyOrNilError (like GetSnapshot).

Two new URI templates are added in uritemplates/links.go. Changes are purely additive (+86 lines, no existing behaviour modified).

Why

Requested during review of OctopusDeploy/cli#589: the new octopus release update-variables and octopus runbook snapshot update-variables commands should call the go client rather than hand-rolling the HTTP request, so the capability is reusable outside the CLI.

Consumer / ordering

OctopusDeploy/cli#589 depends on this PR. Once this merges and a version is tagged, cli#589 will bump its go-octopusdeploy dependency to that version and drop its temporary local replace directive — so cli#589 can be approved/merged as soon as this lands.

Tests

Added validation unit tests for both functions (release_service_test.go, runbook_service_test.go) covering the client/spaceID/id required-parameter checks, following the existing test conventions in each package.

[hnrkndrssn]

Function names should be structured as [Verb][Noun] and as these functions update snapshot variables I've suggested a couple of changes, other than that this is looking good 👍

[Copilot]

Pull request overview

This PR extends the go-octopusdeploy Go client with two new package-level helpers to “re-snapshot” variables for existing Releases and Runbook Snapshots by POSTing to the Octopus Server snapshot-variables endpoints.

Changes:

• Added releases.SnapshotVariables(client, spaceID, releaseID) to POST to the release snapshot-variables endpoint and return the updated Release.
• Added runbooks.SnapshotVariables(client, spaceID, snapshotID) to POST to the runbook snapshot snapshot-variables endpoint and return the updated RunbookSnapshot.
• Added URI template constants plus unit tests covering required-parameter validation.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
uritemplates/links.go	Adds new URI templates for release and runbook snapshot variable re-snapshot endpoints.
pkg/runbooks/runbook_service.go	Introduces SnapshotVariables helper for runbook snapshots.
pkg/runbooks/runbook_service_test.go	Adds validation test coverage for the new runbook helper.
pkg/releases/release_service.go	Introduces SnapshotVariables helper for releases.
pkg/releases/release_service_test.go	Adds validation test coverage for the new release helper.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[justin-newman]

@hnrkndrssn thank you for that feedback. I implemented your suggestions as well as the one from Copilot.

[hnrkndrssn]

Hey @justin-newman just wanted to let you know I've had a look at the latest changes and they're all good now but due to GitHub workflows and required checks I need to take your changes and prepare a new PR that is not from a fork 😞 I'll jump on this first thing on Monday and get this all sorted out.

[justin-newman]

Hey @justin-newman just wanted to let you know I've had a look at the latest changes and they're all good now but due to GitHub workflows and required checks I need to take your changes and prepare a new PR that is not from a fork 😞 I'll jump on this first thing on Monday and get this all sorted out.

No problem, I saw that issue that came up and understand completely. I'm just excited to get that in and work it into my pipelines.

[justin-newman]

@hnrkndrssn could you link that new PR here when you get a chance?

[hnrkndrssn]

@justin-newman yep, I will link the new PR to this original PR 👍