Fix reference to example in README

Signed-off-by: cwasicki <[email protected]>

Author: cwasicki

README.md

@@ -28,7 +28,7 @@ check out the [Contributing Guide](CONTRIBUTING.md).
 
 ## Usage
 
-Please also refer to [examples](https://github.com/frequenz-floss/frequenz-client-reporting-python/tree/HEAD/examples) for more detailed usage.
+Please also refer to source of the [CLI tool](src/frequenz/client/reporting/cli/__main__.py) for a practical example of how to use the client.
 
 ### Installation