Update deploy-smart-contracts.mdx (#310)

Update 'npx hardhat' initialization and .env file syntax in docs

This commit updates the documentation to replace the deprecated 'npx hardhat' command with 'npx hardhat init' for project initialization to align with current Hardhat recommendations. It also modifies the .env file syntax suggestion to include quotes around the WALLET_KEY value, ensuring correct string parsing and preventing potential parsing issues. These changes aim to improve clarity and adherence to best practices for new users setting up Hardhat projects.

apps/base-docs/docs/building-with-base/guides/deploy-smart-contracts.mdx

@@ -75,7 +75,7 @@ npm install --save-dev hardhat
 To create a new Hardhat project, run:
 
 ```bash
-npx hardhat
+npx hardhat init
 ```
 
 Select `Create a TypeScript project` then press _enter_ to confirm the project root.
@@ -149,7 +149,7 @@ npm install --save-dev dotenv
 Once you have `dotenv` installed, you can create a `.env` file with the following content:
 
 ```
-WALLET_KEY=<YOUR_PRIVATE_KEY>
+WALLET_KEY="<YOUR_PRIVATE_KEY>"
 ```
 
 Substituting `<YOUR_PRIVATE_KEY>` with the private key for your wallet.