Overwrite image for docker-compose docs service (#40)

Author: slashmo

docker/docker-compose.1804.50.yaml

@@ -14,3 +14,6 @@ services:
 
   shell:
     image: swift-distributed-tracing:18.04-5.0
+
+  docs:
+    image: swift-distributed-tracing:18.04-5.0

docker/docker-compose.1804.51.yaml

@@ -16,3 +16,6 @@ services:
 
   shell:
     image: swift-distributed-tracing:18.04-5.1
+
+  docs:
+    image: swift-distributed-tracing:18.04-5.1

docker/docker-compose.1804.52.yaml

@@ -16,3 +16,6 @@ services:
 
   shell:
     image: swift-distributed-tracing:18.04-5.2
+
+  docs:
+    image: swift-distributed-tracing:18.04-5.2

docker/docker-compose.1804.53.yaml

@@ -15,3 +15,6 @@ services:
 
   shell:
     image: swift-distributed-tracing:18.04-5.3
+
+  docs:
+    image: swift-distributed-tracing:18.04-5.3

docker/docker-compose.yaml

@@ -42,7 +42,7 @@ services:
       - $SSH_AUTH_SOCK:/tmp/ssh-agent:z
     environment: # FIXME: temp while private
       - SSH_AUTH_SOCK=/tmp/ssh-agent
-      - GIT_SSH_COMMAND=ssh -vv -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no    
+      - GIT_SSH_COMMAND=ssh -vv -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no
     command: /bin/bash -xcl "swift test -Xswiftc -warnings-as-errors $${SANITIZER_ARG-}"
 
   # util