Update the openrc service's retry with the correct format

installation/init.d/pleroma

@@ -12,7 +12,7 @@ export PORT=4000
 export MIX_ENV=prod
 
 # Ask process to terminate within 30 seconds, otherwise kill it
-retry="SIGTERM/30 SIGKILL/5"
+retry="SIGTERM/30/SIGKILL/5"
 
 pidfile="/var/run/pleroma.pid"