matrix: pin synapse to a CPU core

webserver/docker_matrix/templates/docker-compose.yml

-version: "3"
+version: "2.2"
 
 services:
 
@@ -18,6 +18,8 @@ services:
 
     image: matrixdotorg/synapse:v1.21.2
     restart: always
+    cpu_count: "1"
+    cpuset: "0"
     depends_on:
       - db
       - ma1sd