fix: update link to docs

See NordicSemiconductor/asset-tracker-cloud-docs#1020

Author: coderbyheart

README.md

@@ -43,4 +43,4 @@ Alternatively you can use the [GitHub CLI](https://cli.github.com/):
 ---
 
 > :information_source:
-> [Read the complete nRF Asset Tracker documentation](https://nordicsemiconductor.github.io/asset-tracker-cloud-docs/).
+> [Read the complete nRF Asset Tracker documentation](https://docs.nordicsemi.com/bundle/nrf-asset-tracker-saga/).