Tightened the supported versions of solidity

[AntoineRondelet]

While using slither to analyze some contracts written with solidity 0.8 (see here), I got an error (i.e. ERROR:root:unresolved reference to identifier vk.slot ) related to the x.slot syntax introduced in solidity 0.7 as a replacement of the syntax x_slot to retrieve the slot pointed to by the variable x.

See the difference between the solidity 0.7 doc and the solidity 0.6 doc for further details.

That is somewhat confusing, provided that the README states that contracts written with solidity >= 0.4 can be analyzed with the tool, however, I realized (beyond the error above) that the syntax for solidity 0.7 is not yet fully supported: #559

As a consequence, this PR clarifies which solidity versions are currently supported, as a way to remove potential future issues for other users.

[CLAassistant]

All committers have signed the CLA.

[montyly]

Hi @AntoineRondelet.

We support Solidity 0.7, but it looks like we missed the .slot change from the changelog. #833 will fix that.

Let us know if you have other issues with Slither

[AntoineRondelet]

Hi @AntoineRondelet.

We support Solidity 0.7, but it looks like we missed the .slot change from the changelog. #833 will fix that.

Let us know if you have other issues with Slither

Thanks @montyly, no problem. Looking forward to #833 being merged then :)