stepcount 3.13.0

What's Changed

• update GLOSSARY.md by @chanshing in #152
• refactor: simplify min-walk-per-day argument by @chanshing in #153
• fix: specify NA check to only include 'x', 'y', 'z' columns by @chanshing in #156

Full Changelog: v3.12.0...v3.13.0