Resurrect old stack.yaml for lts-9.0 ci job

.travis.yml

@@ -115,7 +115,7 @@ matrix:
   #- env: BUILD=stack ARGS="--resolver lts-7"
   #  compiler: ": #stack 8.0.1"
   #  addons: {apt: {packages: [libgmp-dev]}}
-  - env: BUILD=stack ARGS="--resolver lts-8"
+  - env: BUILD=stack ARGS="--stack-yaml stack-lts-9.0.yaml"
     compiler: ": #stack 8.0.2"
     addons: {apt: {packages: [libgmp-dev]}}
 

stack-lts-9.0.yaml

@@ -0,0 +1,11 @@
+resolver: lts-9.0
+
+extra-deps:
+  - monad-memo-0.4.1
+  - czipwith-1.0.0.0
+  - butcher-1.2.0.0
+  - data-tree-print-0.1.0.0
+  - deque-0.2
+
+packages:
+  - .