ERC20 test with cairo2

[SantiagoPittella]

Add a test for ERC20 contract with Cairo2

Description

Adds:

• ERC20 contract with modifications.
  • Instead of using for max_supply I replaced it with felt252 due to a lack of support on our side.
• A contract that deploys the ERC20 contract.
• A tests that deploys 2 accounts, and uses the deploy contract to deploy to ERC20 with a new token and a token supply for one of the previous accounts, then transfers a certain amount of tokens into the other account. Finally, checks the balances.

Checklist

• Linked to Github Issue
• Unit tests added
• Integration tests added.
• This change requires new documentation.
  • Documentation has been added/updated.

[fmoletta]

Great!

[codecov-commenter]

Codecov Report

Merging #767 (efda09e) into main (8f40853) will increase coverage by 0.13%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #767      +/-   ##
==========================================
+ Coverage   92.50%   92.64%   +0.13%     
==========================================
  Files          50       51       +1     
  Lines       11899    12110     +211     
==========================================
+ Hits        11007    11219     +212     
+ Misses        892      891       -1     

Impacted Files	Coverage Δ
src/testing/mod.rs	100.00% <ø> (ø)
src/lib.rs	98.71% <100.00%> (+<0.01%)	⬆️
src/testing/erc20.rs	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes