eth/abi: enable packed encoding

[q9f]

fix #103

• uint
• int
• bool
• string / bytes
• ufixed
• fixed
• tuple
• hash
• address

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.64%. Comparing base (5d88db2) to head (13917fb).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #211      +/-   ##
==========================================
+ Coverage   99.63%   99.64%   +0.01%     
==========================================
  Files          77       77              
  Lines        4650     4787     +137     
==========================================
+ Hits         4633     4770     +137     
  Misses         17       17              

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