voteProposal() doesnt check that proposalID <= proposalCount.
Recommend that in voteProposal(), require(proposalID <= proposalCount, "Proposal not existent")
It should be <=, because proposalCount is updated before using it (e.g. https://github.com/code-423n4/2021-04-vader/blob/main/vader-protocol/contracts/DAO.sol#L59) in this way the proposal n. 0 is not assignable, although im not sure if its wanted or not.
