chore(docs): update Node.js version in the contribution guide (dotansimha#8984)

Author: ardatan

website/src/pages/docs/custom-codegen/contributing.mdx

@@ -17,7 +17,7 @@ To be able to clone, build and develop codegen, you'll need to have the followin
 
 - [GitHub Account](https://github.com)
 - [Git](https://git-scm.com/downloads)
-- [Node.js](https://nodejs.org/en) (v10/v12/v13)
+- [Node.js](https://nodejs.org/en) (v14+)
 - [Yarn](https://yarnpkg.com) (v1)
 - Any code editor (we recommend [VSCode](https://code.visualstudio.com))