Hi @Cris,
Welcome to the community 
As you are creating a fungible token, I suggest looking at Points to consider when creating a fungible token (ERC20, ERC777)
When creating an upgradeable token, you should also consider the governance around when and how an upgrade would be made.
In general you should be able to use an ERC20 from OpenZeppelin Contracts 3.x with a Crowdsale from OpenZeppelin Contracts 2.x, though you would need to have the Crowdsale and Token in separate projects due to the differing Solidity versions.
You should appropriately test and audit any such solution.
Areas to watch out for is any functionality not covered by the EIP such as minting if you were using a MintedCrowdsale.