Use 5.7 nightlies (#348)

Lukasa · web-flow · commit bd93cc04c68e · 2022-06-13T04:04:04.000-07:00
diff --git a/docker/docker-compose.2004.57.yaml b/docker/docker-compose.2004.57.yaml
@@ -6,7 +6,7 @@ services:
     image: swift-nio-http2:20.04-5.7
     build:
       args:
-        base_image: "swiftlang/swift:nightly-main-focal"
+        base_image: "swiftlang/swift:nightly-5.7-focal"
         h2spec_version: "2.2.1"
 
   unit-tests:
