Solidity 0.7 is a breaking change and we have yet to decide how it fits in the OpenZeppelin Contracts versioning scheme, along with how Solidity 0.6 will be supported moving forward.
This version is for community members who need to use Solidity 0.7 right now.
For everyone else, you can use this version to play with Solidity 0.7, though you may find that not all of the ecosystem supports Solidity 0.7 yet.
I have been playing with a simple ERC20 token inheriting from OpenZeppelin Contracts using Solidity 0.7 and was compiling on Truffle, buidler and OpenZeppelin CLI.
If you are working on upgradeable, or minimal proxy contracts then you will need to wait for the OpenZeppelin Contracts Ethereum Package version to be released (as per timeline above).