update travis script

Author: ulfworsoe

.travis.yml

@@ -11,6 +11,6 @@ git:
 before-install:
   - sudo apt-get install curl
 script:
-  - julia -e 'using Pkg; add(PackageSpec(url=pwd()));'
-  - julia -e 'using Pkg; test("MathOptInterfaceMosek")'
+  - julia -e 'import Pkg; Pkg.add(Pkg.PackageSpec(url=pwd()));'
+  - julia -e 'import Pkg; Pkg.test("MathOptInterfaceMosek")'