Add vcpkg ecosystem support

[JamieMagee]

NOTE: Cannot be merged until the PR in dependabot-core is merged first.

Related:

• add vcpkg ecosystem dependabot/dependabot-core#7644
• Add vcpkg support dependabot/cli#462
• Add vcpkg smoke tests dependabot/smoke-tests#300

[Copilot]

Pull Request Overview

This PR adds initial support for the vcpkg ecosystem by introducing a new Dockerfile and wiring it into the container update flow.

• Register vcpkg in the TypeScript manifest file for container images.
• Add a new vcpkg entry (with placeholder tag) to containers.json.
• Create Dockerfile.vcpkg with a placeholder FROM image.

Reviewed Changes

Copilot reviewed 3 out of 9 changed files in this pull request and generated 3 comments.

File	Description
src/update-containers.ts	Include vcpkg in the manifest passed to write.
docker/containers.json	Add vcpkg key with a placeholder image tag.
docker/Dockerfile.vcpkg	New Dockerfile for vcpkg, currently using TODO.

Comments suppressed due to low confidence (1)

src/update-containers.ts:47

• There’s no existing test for the new vcpkg path. Consider adding a unit or integration test to verify that getImageName('Dockerfile.vcpkg') returns the expected value.

  vcpkg: getImageName('Dockerfile.vcpkg')

[Copilot]

The placeholder TODO in the image tag will cause lookup failures. Please replace it with the actual version and SHA, matching your release process.

Suggested change

	"vcpkg": "ghcr.io/dependabot/dependabot-updater-vcpkg:TODO"
	"vcpkg": "ghcr.io/dependabot/dependabot-updater-vcpkg:v2.0.20250606230616@sha256:1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef"

[Copilot]

The base image reference uses TODO as a tag. Update this to the correct image version (and include a digest if required) to ensure the build succeeds.

Suggested change

	FROM ghcr.io/dependabot/dependabot-updater-vcpkg:TODO
	FROM ghcr.io/dependabot/dependabot-updater-vcpkg:1.2.3

[Copilot]

[nitpick] Consider adding a newline at the end of this Dockerfile to adhere to standard file formatting conventions.