feat: bump codecov to v5

[gfanton]

bump Codecov to v5; this new version should fix CI inconsistency (based on some issue on Codecov)

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.81%. Comparing base (0246761) to head (6ed77c0).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3152      +/-   ##
==========================================
+ Coverage   63.80%   63.81%   +0.01%     
==========================================
  Files         549      549              
  Lines       78833    78833              
==========================================
+ Hits        50300    50308       +8     
+ Misses      25144    25134      -10     
- Partials     3389     3391       +2     

Flag	Coverage Δ
contribs/gnodev	60.54% <ø> (-0.63%)	⬇️
contribs/gnofaucet	14.82% <ø> (-0.95%)	⬇️
gno.land	73.70% <ø> (ø)
gnovm	67.94% <ø> (ø)
misc/genstd	79.72% <ø> (ø)
tm2	62.47% <ø> (+0.04%)	⬆️

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[zivkovicmilos]

🙏 🙏 🙏