support npm v9

[yshrsmz]

resolve #87

• use npx instad of npm bin
• run CI against Node 14, 16, 18(current LTS versions)

[yshrsmz]

CI for Node18 is failing but somehow reports the opposite 🤔

/home/runner/work/action-stylelint/action-stylelint/.//script.sh: 25: Unknown: not found
stylelint version: 

https://github.com/reviewdog/action-stylelint/actions/runs/4284607243/jobs/7461795965

[github-actions[bot]]

🚀 [bumpr] Bumped! New version:v1.16.0 Changes:v1.15.0...v1.16.0