Remove code in preparation for v5.0 (#4258)

Co-authored-by: Ernesto García <ernestognw@gmail.com>
Co-authored-by: Francisco <fg@frang.io>

contracts/security/PullPayment.sol

@@ -1,74 +0,0 @@
-// SPDX-License-Identifier: MIT
-// OpenZeppelin Contracts (last updated v4.8.0) (security/PullPayment.sol)
-
-pragma solidity ^0.8.0;
-
-import "../utils/escrow/Escrow.sol";
-
-/**
- * @dev Simple implementation of a
- * https://consensys.github.io/smart-contract-best-practices/development-recommendations/general/external-calls/#favor-pull-over-push-for-external-calls[pull-payment]
- * strategy, where the paying contract doesn't interact directly with the
- * receiver account, which must withdraw its payments itself.
- *
- * Pull-payments are often considered the best practice when it comes to sending
- * Ether, security-wise. It prevents recipients from blocking execution, and
- * eliminates reentrancy concerns.
- *
- * TIP: If you would like to learn more about reentrancy and alternative ways
- * to protect against it, check out our blog post
- * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
- *
- * To use, derive from the `PullPayment` contract, and use {_asyncTransfer}
- * instead of Solidity's `transfer` function. Payees can query their due
- * payments with {payments}, and retrieve them with {withdrawPayments}.
- */
-abstract contract PullPayment {
-    Escrow private immutable _escrow;
-
-    constructor() {
-        _escrow = new Escrow();
-    }
-
-    /**
-     * @dev Withdraw accumulated payments, forwarding all gas to the recipient.
-     *
-     * Note that _any_ account can call this function, not just the `payee`.
-     * This means that contracts unaware of the `PullPayment` protocol can still
-     * receive funds this way, by having a separate account call
-     * {withdrawPayments}.
-     *
-     * WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities.
-     * Make sure you trust the recipient, or are either following the
-     * checks-effects-interactions pattern or using {ReentrancyGuard}.
-     *
-     * @param payee Whose payments will be withdrawn.
-     *
-     * Causes the `escrow` to emit a {Withdrawn} event.
-     */
-    function withdrawPayments(address payable payee) public virtual {
-        _escrow.withdraw(payee);
-    }
-
-    /**
-     * @dev Returns the payments owed to an address.
-     * @param dest The creditor's address.
-     */
-    function payments(address dest) public view returns (uint256) {
-        return _escrow.depositsOf(dest);
-    }
-
-    /**
-     * @dev Called by the payer to store the sent amount as credit to be pulled.
-     * Funds sent in this way are stored in an intermediate {Escrow} contract, so
-     * there is no danger of them being spent before withdrawal.
-     *
-     * @param dest The destination address of the funds.
-     * @param amount The amount to transfer.
-     *
-     * Causes the `escrow` to emit a {Deposited} event.
-     */
-    function _asyncTransfer(address dest, uint256 amount) internal virtual {
-        _escrow.deposit{value: amount}(dest);
-    }
-}

contracts/security/README.adoc

@@ -5,7 +5,6 @@ NOTE: This document is better viewed at https://docs.openzeppelin.com/contracts/
 
 These contracts aim to cover common security practices.
 
-* {PullPayment}: A pattern that can be used to avoid reentrancy attacks.
 * {ReentrancyGuard}: A modifier that can prevent reentrancy during certain functions.
 * {Pausable}: A common emergency response mechanism that can pause functionality while a remediation is pending.
 
@@ -13,8 +12,6 @@ TIP: For an overview on reentrancy and the possible mechanisms to prevent it, re
 
 == Contracts
 
-{{PullPayment}}
-
 {{ReentrancyGuard}}
 
 {{Pausable}}