Bumps gonum.org/v1/gonum from 0.8.2 to 0.12.0.


[![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=gonum.org/v1/gonum&package-manager=go_modules&previous-version=0.8.2&new-version=0.12.0)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores)

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[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

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