fix(release): update Go version to 1.25 and migrate to homebrew_casks

[platinummonkey]

Summary

Fixes two critical issues preventing successful releases:

1. Outdated Go version (1.21 → 1.25)
2. Deprecated GoReleaser brews configuration

Problem 1: Go Version

The release workflow was using Go 1.21, which is outdated and may cause compatibility issues with newer dependencies.

Problem 2: Deprecated brews Configuration

GoReleaser v2.10+ deprecated the brews field with warning:

brews is being phased out in favor of homebrew_casks

Changes

.github/workflows/release.yml

• Updated go-version from 1.21 to 1.25

.goreleaser.yml

• Migrated from brews: to homebrew_casks:
• Removed deprecated directory: Formula field
• Converted to modern configuration format:
  • binaries: [pup] - explicit binary declaration
  • Simplified completions structure
  • Added url.verified field for Homebrew audit compliance
• Updated commit message template from "formula" to "cask"

Migration Details

The new homebrew_casks configuration provides:

• Better alignment with GoReleaser v2.x architecture
• Cleaner, more maintainable configuration
• Support for shell completions built-in
• Homebrew audit compliance via verified URL

Testing

• Configuration validated against GoReleaser v2.13.3 documentation
• Syntax follows GoReleaser's own .goreleaser.yaml conventions
• Will be tested when release workflow runs after merge

Related Issues

Fixes release workflow run #21914250220

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🤖 Generated with Claude Code

[github-actions]

📊 Test Coverage Report

Overall Coverage: 81.7%

Threshold: 80% ✅

Coverage by Package

## Coverage by Package

- github.com/DataDog/pup/pkg/auth/callback/server.go:40: 81.2%
- github.com/DataDog/pup/pkg/auth/dcr/client.go:28: 100.0%
- github.com/DataDog/pup/pkg/auth/dcr/types.go:24: 100.0%
- github.com/DataDog/pup/pkg/auth/oauth/client.go:22: 100.0%
- github.com/DataDog/pup/pkg/auth/oauth/pkce.go:24: 85.7%
- github.com/DataDog/pup/pkg/auth/storage/factory.go:53: 94.7%
- github.com/DataDog/pup/pkg/auth/storage/keychain.go:44: 42.9%
- github.com/DataDog/pup/pkg/auth/storage/storage.go:58: 71.4%
- github.com/DataDog/pup/pkg/auth/types/types.go:23: 100.0%
- github.com/DataDog/pup/pkg/client/client.go:32: 94.4%
- github.com/DataDog/pup/pkg/config/alias.go:26: 100.0%
- github.com/DataDog/pup/pkg/config/config.go:22: 100.0%
- github.com/DataDog/pup/pkg/formatter/formatter.go:31: 100.0%
- github.com/DataDog/pup/pkg/useragent/useragent.go:32: 100.0%
- github.com/DataDog/pup/pkg/util/time.go:20: 95.8%

## Summary

total:								(statements)		81.7%

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📈 Coverage Status: ✅ PASSED - Coverage meets minimum threshold

_{Updated for commit 4ff4a10}