Switch the stack resolver to nightly-2018-05-23 to support GHC-8.4.2

Author: basvandijk

.travis.yml

@@ -31,7 +31,7 @@ addons:
 # The different configurations we want to test. You could also do things like
 # change flags or use --stack-yaml to point to a different file.
 env:
-- ARGS="--jobs 2 --resolver lts-10.2" CACHE_NAME=LTS_10_2_CV_3_4_0
+- ARGS="--jobs 2 --resolver nightly-2018-05-23" CACHE_NAME=NIGHTLY_2018_05_23_CV_3_4_0
 
 before_install:
 # Install OpenCV 3

stack.yaml

@@ -1,4 +1,4 @@
-resolver: lts-10.2
+resolver: nightly-2018-05-23
 packages:
 - opencv/
 - opencv-examples/
@@ -7,9 +7,6 @@ packages:
 flags: {}
 allow-newer: true
 
-extra-deps:
-- repa-3.4.1.3
-
 extra-lib-dirs:
 - /usr/local/lib