add docker-compose setup for amazon linux (#114)

motivation: swift 5.2.4 now supportes AL2

changes:
* add docker-compose file for al2 5.2.4
* correct 5.3 docker-file to say al2 instead of 18.04

docker/Dockerfile

@@ -1,7 +1,6 @@
 ARG swift_version=5.2
 # FIXME when 5.2 images are available
-#ARG base_image=swift:$swift_version-amazonlinux2
-ARG base_image=swiftlang/swift:nightly-amazonlinux2
+ARG base_image=swift:$swift_version-amazonlinux2
 FROM $base_image
 # needed to do again after FROM due to docker limitation
 ARG swift_version

docker/docker-compose.al2.52.yaml

@@ -0,0 +1,18 @@
+version: "3"
+
+services:
+
+  runtime-setup:
+    image: swift-aws-lambda:al2-5.2
+    build:
+      args:
+        swift_version: "5.2"
+
+  test:
+    image: swift-aws-lambda:al2-5.2
+
+  test-samples:
+    image: swift-aws-lambda:al2-5.2
+
+  shell:
+    image: swift-aws-lambda:al2-5.2

docker/docker-compose.al2.53.yaml

@@ -3,16 +3,16 @@ version: "3"
 services:
 
   runtime-setup:
-    image: swift-aws-lambda:18.04-5.3
+    image: swift-aws-lambda:al2-5.3
     build:
       args:
         base_image: "swiftlang/swift:nightly-amazonlinux2"
 
   test:
-    image: swift-aws-lambda:18.04-5.3
+    image: swift-aws-lambda:al2-5.3
 
   test-samples:
-    image: swift-aws-lambda:18.04-5.3
+    image: swift-aws-lambda:al2-5.3
 
   shell:
-    image: swift-aws-lambda:18.04-5.3
+    image: swift-aws-lambda:al2-5.3