separate section for solidity < 0.8.0

[devtooligan]

Some older vulns like Uninitialized Storage Pointer are no longer applicable and should be excluded from the main sections and put in their own separate section for solidity < 0.8.0

If you're interested in this idea I can take a stab at a pr.

[kadenzipfel]

Currently there should be a warning on deprecated vulnerabilities, e.g. https://github.com/kadenzipfel/smart-contract-vulnerabilities/blob/master/vulnerabilities/incorrect-constructor.md, although some may be missing

My only concern with this approach is that some <0.8.0 vulns are still worth learning in case you're reviewing an old codebase so I wouldn't necessarily want people to skip over them

Maybe the best approach is to have a * next to them in the readme or something like that?