add julia v1.3 to travis tests (#633)

update travis tests to Julia v1.3

Author: ccoffrin

.travis.yml

@@ -4,7 +4,7 @@ os:
   - osx
 julia:
   - 1.0
-  - 1.2
+  - 1.3
   - nightly
 matrix:
   allow_failures:
@@ -13,7 +13,7 @@ codecov: true
 jobs:
   include:
     - stage: "Documentation"
-      julia: 1.1
+      julia: 1.3
       os: linux
       script:
         - julia --project=docs/ -e 'using Pkg; Pkg.instantiate(); Pkg.develop(PackageSpec(path=pwd()))'