update ci setup

motivation: 5.2 adoption, prepare for 5.3

changes:
* add 5.2 docker-compose setup
* add 5.3 docker-compose setup (placeholder)

Author: tomerd

docker/docker-compose.1804.52.yaml

@@ -6,7 +6,8 @@ services:
     image: swift-aws-lambda:18.04-5.2
     build:
       args:
-        base_image: "swiftlang/swift:nightly-5.2-bionic"
+        ubuntu_version: "bionic"
+        swift_version: "5.2"
 
   test:
     image: swift-aws-lambda:18.04-5.2

docker/docker-compose.1804.53.yaml

@@ -0,0 +1,15 @@
+version: "3"
+
+services:
+
+  runtime-setup:
+    image: swift-aws-lambda:18.04-5.3
+    build:
+      args:
+        base_image: "swiftlang/swift:nightly-bionic"
+
+  test:
+    image: swift-aws-lambda:18.04-5.3
+
+  shell:
+    image: swift-aws-lambda:18.04-5.3