make ERC2981:royaltyInfo public (OpenZeppelin#3305)

Author: Amxx

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## Unreleased
+ * `ERC2981`: make `royaltiInfo` public to allow super call in overrides. ([#3305](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3305))
+
 ## Unreleased
 
  * `crosschain`: Add a new set of contracts for cross-chain applications. `CrossChainEnabled` is a base contract with instantiations for several chains and bridges, and `AccessControlCrossChain` is an extension of access control that allows cross-chain operation. ([#3183](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3183))

contracts/token/common/ERC2981.sol

@@ -40,13 +40,7 @@ abstract contract ERC2981 is IERC2981, ERC165 {
     /**
      * @inheritdoc IERC2981
      */
-    function royaltyInfo(uint256 _tokenId, uint256 _salePrice)
-        external
-        view
-        virtual
-        override
-        returns (address, uint256)
-    {
+    function royaltyInfo(uint256 _tokenId, uint256 _salePrice) public view virtual override returns (address, uint256) {
         RoyaltyInfo memory royalty = _tokenRoyaltyInfo[_tokenId];
 
         if (royalty.receiver == address(0)) {