Add missing LF to last line in config/haproxy.cfg (#97)

A missing LF in the last line is currently a warning, but will become a hard error with HAProxy 2.3.

Author: tosie

config/haproxy.cfg

@@ -35,4 +35,4 @@ backend bk_db
     http-check expect string leader
     http-check disable-on-404
     server-template pg 10 $PRIMARY_REGION.$FLY_APP_NAME.internal:5433 check port 5500 resolvers flydns resolve-prefer ipv6 init-addr none on-marked-down shutdown-sessions
-    server pg [$PG_LISTEN_ADDRESS]:5433 check backup port 5500 on-marked-down shutdown-sessions
+    server pg [$PG_LISTEN_ADDRESS]:5433 check backup port 5500 on-marked-down shutdown-sessions