BitDAO uses msg.sender rather than _msgSender()

[CjHare]

The BitDAO contract extends ERC20 contract uses the Context (supporting Ethereum Gas Station Network v1) contract.

To accommodate the GSN contracts need to replace msg.sender with _msgSender(), as when using the GSN the msg.sender` is not the actual sender but the GSN contract.

The BitDAO only uses msg.sender, which may cause issues if BITs are ever used with the GSN

	modifier onlyAdmin {
		require(msg.sender == admin, 'Caller is not a admin');
		_;
	}```

``` line 836 – BitDAO.sol
	function setPendingAdmin(address newPendingAdmin) external returns (bool) {
		if (msg.sender != admin) {
			revert('BitDAO:setPendingAdmin:illegal address');
		}
...

	function acceptAdmin() external returns (bool) {
		if (msg.sender != pendingAdmin || msg.sender == address(0)) {
			revert('BitDAO:acceptAdmin:illegal address');
		}
...

	function delegate(address delegatee) external {
		return _delegate(msg.sender, delegatee);
	}

There could be a case for these operations to require direct calls (excluding all intermediary/proxy contracts, such as GSN), however was that the intention?