turn thirdwebFee address private

Author: Krishang Nadgauda

contracts/drop/SignatureDrop.sol

@@ -67,7 +67,7 @@ contract SignatureDrop is
     uint256 private constant MAX_BPS = 10_000;
 
     /// @dev The thirdweb contract with fee related information.
-    ITWFee public immutable thirdwebFee;
+    ITWFee private immutable thirdwebFee;
 
     /// @dev Owner of the contract (purpose: OpenSea compatibility)
     address private _owner;

docs/SignatureDrop.md

@@ -917,23 +917,6 @@ function symbol() external view returns (string)
 |---|---|---|
 | _0 | string | undefined
 
-### thirdwebFee
-
-```solidity
-function thirdwebFee() external view returns (contract ITWFee)
-```
-
-
-
-*The thirdweb contract with fee related information.*
-
-
-#### Returns
-
-| Name | Type | Description |
-|---|---|---|
-| _0 | contract ITWFee | undefined
-
 ### tokenURI
 
 ```solidity