Update podspec homepage to fix react native link
Update podspec homepage to fix react native link

I kept on getting the following error when running `react native link`
```
[!] The `react-native-static-server` pod failed to validate due to 1 error:
    - ERROR | attributes: Missing required attribute `homepage`.
    - WARN  | source: Git sources should specify a tag.
    - WARN  | description: The description is equal to the summary.
```

Switching the homepage to point at the repository link fixes this.
futurepress/react-native-static-server,futurepress/react-native-static-server,futurepress/react-native-static-server,futurepress/react-native-static-server,futurepress/react-native-static-server