Add Cairo lang and OZ Contracts versions to generated contracts

[martriay]

Right now users have no way of knowing what OZ Contracts version they're generating nor what Cairo compiler version to use with. We can add these in the comments (right next to the licence).

Another alternative is to specify just Contracts version and have (assume?) a mapping between OZ Contracts <> Cairo version.

[ericglau]

For Solidity, we plan to convey semantic versioning for the OZ Contracts version like this:

// SPDX-License-Identifier: MIT
// Compatible with OpenZeppelin Contracts ^5.0.0
pragma solidity ^0.8.20;

@martriay @ericnordelo @andrew-fleming For Cairo, does it make sense to also convey semantic versioning for Cairo lang itself? For example, something like:

// SPDX-License-Identifier: MIT
// Compatible with OpenZeppelin Contracts for Cairo ^0.8.0
// Cairo lang ^2.3.1

(or // Cairo compiler ^2.3.1)

[martriay]

Looks good! Although I'd be very specific with the versions since Cairo is introducing breaking changes even in minor releases. We cannot guarantee compatibility with any future version.

[ericglau]

@martriay In that case we should either do // Cairo lang 2.3.1 for a specific version (which is slightly misleading if it does work with a newer version of Cairo), or omit the Cairo version. Which would you suggest?

[martriay]

Specific version > no version