.env.example

### 💭 Description

.env.example has missing field

`NEXT_PUBLIC_APPWRITE_PROJECT_NAME =`

Connect your platform in the Console gives the following values
```
NEXT_PUBLIC_APPWRITE_PROJECT_ID =
NEXT_PUBLIC_APPWRITE_PROJECT_NAME =
NEXT_PUBLIC_APPWRITE_ENDPOINT =
```

But the .env.example in this repository only have
```
NEXT_PUBLIC_APPWRITE_PROJECT_ID=
NEXT_PUBLIC_APPWRITE_ENDPOINT=
```

### 👀 Have you spent some time to check if this issue has been raised before?

- [x] I checked and didn't find similar issue

### 🏢 Have you read the Code of Conduct?

- [x] I have read the [Code of Conduct](https://github.com/appwrite/.github/blob/main/CODE_OF_CONDUCT.md)

Open .env.example and compare its Appwrite variables with the three values listed in the issue. Add the missing project-name entry, then verify the example includes all three required variables with the same formatting.

Written by the indexing model from the issue text.