Port UUPSProxy to support Solidity 0.5.x

[frangio]

Hi @maxweng. Are you using the Upgrades Plugins? You can switch to UUPS proxies by just changing the options when you depoy the proxy.

You will need to port the UUPSUpgradeable contract to 0.5, but it should be small changes.

UUPS Proxies: Tutorial (Solidity + JavaScript)

UUPS Proxies: A Tutorial In this tutorial we will deploy an upgradeable contract using the UUPS proxy pattern. We assume some familiarity with Ethereum upgradeable proxies. Introduction to UUPS The original proxies included in OpenZeppelin followed the Transparent Proxy Pattern. While this pattern is still provided, our recommendation is now shifting towards UUPS proxies, which are both lightweight and versatile. The name UUPS comes from EIP1822, which first documented the pattern. While bot…