* add AddressToUintMap

* Update contracts/utils/structs/EnumerableMap.sol

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* address comments

* lint code

* merge mocks into a single file

* add PR link to changelog entry

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>
Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Remove repeated word "the".

* add a virtual _onlyRole(bytes32) modifier

* _onlyRole(role) → _checkRole(role)

* update doc

* Make royaltyInfo(uint256 _tokenId, uint256 _salePrice) virtual

Should be cherrypicked in release 4.5

* fix lint

Change `ERC2891` > `ERC2981`.

* Update ERC777.sol

* Update ERC777.sol

* Update ERC777.sol

* Update ERC777.sol

* fix revert reasons

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Han Lin Yap <codler@users.noreply.github.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* add contract and tests

* avoid implicit cast

* add test cases

* fix test names

* modify avarage and add tests

* improve signed average formula

* fix lint

* better average formula

* refactor signed average testing

* add doc and changelog entry

* Update contracts/utils/math/SignedMath.sol

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* remove ceilDiv

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
Co-authored-by: Francisco Giordano <frangio.1@gmail.com>