Update dependencies

roles/matrix-server/defaults/main.yml

@@ -63,9 +63,9 @@ docker_postgres_image_v9: "postgres:9.6.9-alpine"
 docker_postgres_image_v10: "postgres:10.4-alpine"
 docker_postgres_image_latest: "{{ docker_postgres_image_v10 }}"
 
-docker_matrix_image: "matrixdotorg/synapse:v0.31.2"
-docker_nginx_image: "nginx:1.15.0-alpine"
-docker_riot_image: "avhost/docker-matrix-riot:v0.15.6"
+docker_matrix_image: "matrixdotorg/synapse:v0.33.0"
+docker_nginx_image: "nginx:1.15.1-alpine"
+docker_riot_image: "avhost/docker-matrix-riot:v0.15.7"
 docker_s3fs_image: "xueshanf/s3fs:latest"
 docker_goofys_image: "cloudproto/goofys:latest"
 docker_coturn_image: "instrumentisto/coturn:4.5.0.7"