ci: update to node 26 in GitHub workflow

[sebastijankuzner]

Summary

Checklist

• Ready to be merged

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.60%. Comparing base (72cd6f1) to head (62a3d32).

Additional details and impacted files

@@             Coverage Diff              @@
##           develop    #1287       +/-   ##
============================================
+ Coverage    56.67%   98.60%   +41.92%     
============================================
  Files         1123        3     -1120     
  Lines        64897      430    -64467     
  Branches      1771       77     -1694     
============================================
- Hits         36782      424    -36358     
+ Misses       27885        4    -27881     
+ Partials       230        2      -228     

Flag	Coverage Δ
contracts	98.60% <ø> (?)
packages	?

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[sebastijankuzner]

Waiting for LTS.