bump dependencies and fix comments

Author: MoMannn

CONTRIBUTING.md

@@ -18,9 +18,8 @@ The full style guide is available [here](https://github.com/0xcert/solidity-styl
 
 The release manager is responsible to follow this process for each release of this project.
 
-1. Confirm that the [version we reference](https://github.com/0xcert/ethereum-erc721/blob/master/src/contracts/math/safe-math.sol) for SafeMath is the [latest released version](https://github.com/0xcert/framework/tree/master/packages/0xcert-ethereum-utils-contracts/src/contracts/math).
-2. Summarize the changes and create a release using [GitHub releases](https://github.com/0xcert/solidity-style-guide/releases).
-3. Create a branch/pull request against https://github.com/0xcert/framework/tree/master/packages/0xcert-ethereum-erc721-contracts for any relevant changes since the last release here
+1. Summarize the changes and create a release using [GitHub releases](https://github.com/0xcert/solidity-style-guide/releases).
+2. Create a branch/pull request against https://github.com/0xcert/framework/tree/master/packages/0xcert-ethereum-erc721-contracts for any relevant changes since the last release here
 
 ```
 $ npm i