Note: You should only use code published in an official release of OpenZeppelin Contracts, the latest release is 2.5. When importing via GitHub on Remix you can specify the release tag, (otherwise you will get the latest code in the master branch).
Please see the following example of importing OpenZeppelin Contracts from Remix:
Note: You should only use code published in an official release of OpenZeppelin Contracts, the latest release is 2.5. When importing via GitHub on Remix you can specify the release tag, (otherwise you will get the latest code in the master branch).