Summa.sol : Ownable: Does not implement 2-Step-Process for transferring ownership

[zzzuhaibmohd]

Describe the bug
The contracts Summa.sol does not implement a 2-Step-Process for transferring ownership.
So ownership of the contract can easily be lost when making a mistake when transferring ownership.

While the probability if this happening is highly unlikely, it is better to follow best security measures.

To Reproduce
Summa.sol#L7

Expected behavior
Consider using the Ownable2Step contract from OZ (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable2Step.sol) instead.

The way it works is there is a transferOwnership to transfer the ownership and acceptOwnership to accept the ownership. Refer to Ownable2Step.sol contract linked above.

Additional context
Add any other context about the problem here.