Add a findLowerBound function to the Arrays library

[Amxx]

Has request by @alanarvelo during DevConnect, we should add a lower lookup function to Arrays.sol. This is already available in Checkpoints but is missing from Arrays.

[basefee]

Does this issue also require writing test case for the new function?

[kamuikatsurgi]

Hey! I can contribute to this, can someone explain me what exactly is needed for the findLowerBound function in Arrays.sol library? @Amxx

[Amxx]

@kamuikatsurgi we already have an implementation and are discussing backward compatibility issues.
Thank you for your proposal though

[kamuik16]

@kamuikatsurgi we already have an implementation and are discussing backward compatibility issues. Thank you for your proposal though

Hey @Amxx, any beginner friendly or good first issue I can work on right now?

[Amxx]

@kamuik16 nothing really comes to mind right now. We have some ideas for new features, but they are quite difficult/tricky to figure out.