add nightly with GHC 8.8

Author: bitonic

.travis.yml

@@ -19,6 +19,7 @@ addons:
 matrix:
   include:
    - env: ARGS="--flag inline-c:gsl-example"
+   - env: ARGS="--stack-yaml stack-nightly-2020-01-30.yaml --flag inline-c:gsl-example"
    - env: ARGS="--stack-yaml stack-lts-12.26.yaml --flag inline-c:gsl-example"
    - env: ARGS="--stack-yaml stack-lts-11.22.yaml --flag inline-c:gsl-example"
    - os: osx

stack-nightly-2020-01-30.yaml

@@ -0,0 +1,10 @@
+resolver: nightly-2020-01-30
+packages:
+- inline-c
+- inline-c-cpp
+- sample-cabal-project
+extra-deps:
+- Chart-cairo-1.9.3@sha256:05cecda5743954e43c8eabea788e0c19300c305346febee727ce578f69e30748,879
+- cairo-0.13.8.0@sha256:9b64a376ebaa4f153bba5866a32291fd4bed48147009cce9158ce6533928eba8,4075
+- gtk2hs-buildtools-0.13.8.0@sha256:132f38155fc677430a47ea750918973161c876fb6f281d342ac2f07eb99229ce,5238
+