chore: improve ci test reports with gotestsum

[sweatybridge]

What kind of change does this PR introduce?

ci

What is the new behavior?

• Run tests with gotestsum for clearer reporting.
• Version controls linter and test runner in go.mod.

Additional context

Add any other context or screenshots.

[coveralls]

Pull Request Test Coverage Report for Build 7384085034

Warning: This coverage report may be inaccurate.

We've detected an issue with your CI configuration that might affect the accuracy of this pull request's coverage report.
To ensure accuracy in future PRs, please see these guidelines.
A quick fix for this PR: rebase it; your next report should be accurate.

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.06%) to 58.266%

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Totals
Change from base Build 7381761562:	-0.06%
Covered Lines:	6002
Relevant Lines:	10301

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💛 - Coveralls