Update env.j2

roles/custom/matrix-element-call/templates/env.j2

@@ -1,7 +1,7 @@
 # Environment variables for Element Call
 ELEMENT_CALL_SERVER_URL=https://{{ matrix_element_call_domain }}
 LIVEKIT_KEY=devkey
-LIVEKIT_SERVICE_URL={{ matrix_element_call_livekit_service_url }}
+LIVEKIT_URL={{ matrix_element_call_livekit_service_url }}
 LIVEKIT_SECRET={{ matrix_element_call_jwt_secret }}
 JWT_SERVICE_URL={{ matrix_element_call_jwt_service_url }}