Bump go-git to latest, includes workaround for x/crypto ssh hostkey selection

[JohnStarich]

• Bump go-git to latest, includes workaround for x/crypto ssh hostkey selection build(deps): bump golang.org/x/crypto from 0.0.0-20210921155107-089bfa567519 to 0.1.0 in /gopages #45 (review)
• Explicitly check out default branch before clone in tests. Fixes pipe: Failed to push gopages commit: command error on refs/heads/gh-pages: branch is currently checked out
• Reformat octal numbers with latest gofmt
• Bump minimum supported Go version to 1.19 to match dependencies
• Use nil auth method if no gh-pages token or user provided

[github-actions]

Diff coverage is below target. Add tests for these files:

	Lines	Coverage	File
🟠	9/15	60.0% ██▉	gopages/main.go