Fix Travis build (at least, try to)

Author: Clément Le Provost

.travis.yml

@@ -9,6 +9,8 @@ env:
     - PLATFORM="iOS"    SDK="iphonesimulator9.3"    DESTINATION="OS=8.1,name=iPhone 6"
     - PLATFORM="iOS"    SDK="iphonesimulator9.3"    DESTINATION="OS=9.3,name=iPhone 6"
     - PLATFORM="tvOS"   SDK="appletvsimulator9.2"   DESTINATION="OS=9.2,name=Apple TV 1080p"
+install:
+  - pod install --repo-update
 before_script:
   - gem install xcpretty -N
 script: