chore: add dependabot configuration for GitHub Actions updates

[daizutabi]

No description provided.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.32%. Comparing base (e85f44c) to head (0500c6a).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #255   +/-   ##
=======================================
  Coverage   96.32%   96.32%           
=======================================
  Files           6        6           
  Lines        1006     1006           
=======================================
  Hits          969      969           
  Misses         37       37           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.