Upgrade to Openzeppelin V5

[0xSamWitch]

OZ recently released a major upgrade https://blog.openzeppelin.com/introducing-openzeppelin-contracts-5.0 these contracts should be updated to resolve the backwards incompatible changes

[e00dan]

Additional context from the perspective of new developers following quick-start guide from LayerZero docs but trying to use Foundry instead of using this repository and Hardhat:

When setting up Foundry and installing OpenZeppelin libraries by default it will install latest version (>= 5). This results in the error in OmniCounter example:

➜  lzcross git:(master) ✗ forge build
[⠊] Compiling...
[⠊] Installing Solc version 0.8.23
[⠔] Successfully installed Solc 0.8.23
[⠊] Compiling 35 files with 0.8.23
[⠢] Solc 0.8.23 finished in 459.69ms
Error: 
Compiler run failed:
Error (3415): No arguments passed to the base constructor. Specify the arguments or mark "OmniCounter" as abstract.
 --> src/OmniCounter.sol:9:1:
  |
9 | contract OmniCounter is NonblockingLzApp {
  | ^ (Relevant source part starts here and spans across multiple lines).
Note: Base constructor parameters:
  --> lib/openzeppelin-contracts/contracts/access/Ownable.sol:38:16:
   |
38 |     constructor(address initialOwner) {
   |  

Seems easily fixable though by changing constructor in LzApp.sol to:

constructor(address _endpoint) Ownable(_msgSender()) {
    lzEndpoint = ILayerZeroEndpoint(_endpoint);
}