Fix CI and add test for ERC721Transfers()

[nanmu42]

fixes #64 .

[codecov]

Codecov Report

Merging #65 (9e13132) into master (4bf649f) will increase coverage by 0.24%.
The diff coverage is 82.35%.

@@            Coverage Diff             @@
##           master      #65      +/-   ##
==========================================
+ Coverage   76.75%   77.00%   +0.24%     
==========================================
  Files          10       10              
  Lines         370      387      +17     
==========================================
+ Hits          284      298      +14     
- Misses         59       61       +2     
- Partials       27       28       +1     

Impacted Files	Coverage Δ
account.go	91.74% <82.35%> (-1.74%)	⬇️

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