Keep coverage stable by using a fixed juila version.

Author: Chris Foster

.travis.yml

@@ -29,4 +29,6 @@ jobs:
 
 after_success:
 #  - julia -e 'Pkg.add("Unitful")' ?
-  - julia -e 'using Pkg; Pkg.add("Coverage"); using Coverage; Coveralls.submit(process_folder())'
+  - if [ $TRAVIS_JULIA_VERSION = "1.0" ] && [ $TRAVIS_OS_NAME = "linux" ]; then
+      julia -e 'using Pkg; Pkg.add("Coverage"); using Coverage; Coveralls.submit(process_folder())'
+    fi