Bump attestant go-eth2-client to 0.16.3 and go-builder-client to 0.3.0

[avalonche]

📝 Summary

⛱ Motivation and Context

📚 References

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✅ I have run these commands

• make lint
• make test-race
• go mod tidy

[codecov-commenter]

Codecov Report

Merging #505 (4de54f9) into main (9ad7f5a) will decrease coverage by 0.24%.
The diff coverage is 0.00%.

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@@            Coverage Diff             @@
##             main     #505      +/-   ##
==========================================
- Coverage   69.05%   68.81%   -0.24%     
==========================================
  Files           8        8              
  Lines        1270     1270              
==========================================
- Hits          877      874       -3     
- Misses        345      346       +1     
- Partials       48       50       +2     

Flag	Coverage Δ
unittests	68.81% <0.00%> (-0.24%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
server/mock_relay.go	88.44% <0.00%> (ø)

... and 1 file with indirect coverage changes

[metachris]

Thanks! Please check the linter.