fix: register go-test-coverage tool in tools/go.mod

[Valyrian-Code]

Description

The GO_TEST_COVERAGE Makefile variable referenced the coverage tool via
go tool github.com/vladopajic/go-test-coverage/v2, but the tool was not
registered in any module's tool directive, so make go-test-with-coverage
and make validate-test-coverage failed to resolve it.

This registers github.com/vladopajic/go-test-coverage/v2 in tools/go.mod
(alongside the other tooling dependencies) and updates the Makefile invocation
to use -modfile tools/go.mod, matching the existing yamlfmt and goreleaser
patterns.

Verified locally: go tool -modfile tools/go.mod github.com/vladopajic/go-test-coverage/v2 --help
now resolves and runs the tool.

Fixes #12575

Change Type

/kind fix

Changelog

NONE

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR updates the repository’s Go tooling setup to run go-test-coverage via the dedicated tools/go.mod module.

Changes:

• Add github.com/vladopajic/go-test-coverage/v2 to the tools module toolchain.
• Update tools/go.mod / tools/go.sum with transitive dependencies required by the new tool.
• Adjust the Makefile to invoke go-test-coverage using -modfile tools/go.mod.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 3 comments.

File	Description
tools/go.mod	Registers go-test-coverage as a tool and records new indirect dependencies in the tools module.
tools/go.sum	Captures module checksums for the newly introduced tool/transitive dependencies.
Makefile	Runs go-test-coverage using the tools module via -modfile tools/go.mod.

[Valyrian-Code]

Thanks for the review. I looked into all three points:

1. -modfile and workspace mode — This repo doesn't use Go workspace mode (there's no go.work file and GOWORK is unset), so -modfile is safe here. It also matches the existing convention in this same Makefile: YAMLFMT ?= go tool -modfile tools/go.mod yamlfmt and the release target (goreleaser) both use the identical pattern. If a workspace-safe form is preferred regardless, the setup-envtest line uses go -C tools tool … — happy to switch to that for consistency if you'd rather.

2. aws/aws-sdk-go (v1) — This is a required transitive dependency of the coverage tool itself, not something avoidable on our side. go mod why traces it to the tool's badge uploader (which backs the --cdn-* flags):

github.com/vladopajic/go-test-coverage/v2/pkg/testcoverage/badgestorer
github.com/aws/aws-sdk-go/aws

go mod tidy won't drop it since it's genuinely in the tool's import graph — removing it would require an upstream change in go-test-coverage.

3. Two go-github majors (v82 + v84) — v84 already existed in tools/go.mod on main (pulled in by goreleaser) before this PR; this change only adds v82, which the same badgestorer package imports. They're distinct module paths and coexist fine; consolidating would likewise need upstream alignment, not something this PR can do.

Net: the only first-party change here is the one-line Makefile invocation plus registering the tool — the additional go.mod/go.sum entries are the tool's own required transitive dependencies. Let me know if you'd prefer the go -C tools tool form.

[Valyrian-Code]

Gentle ping on this one. It's a small fix that's been open a few weeks, would appreciate a review whenever a maintainer has time. Thanks!

[davidjumani]

@Valyrian-Code can you please fix the failing checks. This can be done by running make verify and updating the PR