chore(teslamate): Update Teslamate Docker image source to GHCR

The official Teslamate Docker images have migrated from Docker Hub to
GitHub Container Registry (GHCR). This update ensures that the
`docker-compose.yml` pulls the Teslamate image from the correct and
official source.

teslamate/docker-compose.yml

@@ -1,6 +1,6 @@
 services:
   teslamate:
-    image: teslamate/teslamate:latest
+    image: ghcr.io/teslamate/teslamate:latest
     restart: always
     environment:
       - ENCRYPTION_KEY=/run/secrets/password