Make the relative link to examples work from the refinery folder (#318)

Make the relative link to example work from the refinery folder

README.md

@@ -50,8 +50,7 @@ fn main() {
 }
 ```
 
-For more library examples, refer to the [`examples`](examples).
-
+For more library examples, refer to the [`examples`](https://github.com/rust-db/refinery/tree/main/examples).
 ### Example: CLI
 
 NOTE: