docs(README.md): clarify reason for archiving (#123)

Signed-off-by: Mete Fatih Cırıt <mfc@autoware.org>

Author: xmfcx

README.md

@@ -1 +1,14 @@
 # sample_sensor_kit_launch
+
+🗃️ This is an archived repository.
+
+The contents of this repository are now moved to [autoware_launch](https://github.com/autowarefoundation/autoware_launch) repository.
+
+The packages from this repository now live under the `autoware_launch/sensor_kit` directory.
+
+**The reason** for this move is to consolidate all the launch files in one repository to make it easier to maintain and manage.
+
+**Related issue:** [Move launch and parameter packages into autoware_launch #5912](https://github.com/autowarefoundation/autoware/issues/5912)
+
+In the far future, the launch file structure will be updated more drastically to make them more modular and easier to use.
+But for those updates, please follow the [autoware_launch](https://github.com/autowarefoundation/autoware_launch) repository.