fix: update docs and errors with CKANError

docs/content/docs/index.mdx

@@ -11,10 +11,11 @@ This means that instead of using generic request library crates such as `reqwest
 For example the following code can be ran to send an HTTP POST request to the `/package_list` endpoint of a local CKAN instance's API by using the `ckanaction` crate:
 
 ```rust
+use ckanaction::CKANError;
 use dotenvy::dotenv;
 
 #[tokio::main]
-async fn main() -> Result<(), Box<dyn std::error::Error>> {
+async fn main() -> Result<(), CKANError> {
     // Load environment variables from .env file
     dotenv()?;