Use prerelease version of CocoaPods on CI

sharplet · sharplet · commit 7b150abe2098 · 2019-01-07T11:15:24.000-05:00
This allows us to use CocoaPods 1.6.0.beta, which fixes a bug in
`pod lib lint` under Xcode 10.
diff --git a/.travis.yml b/.travis.yml
@@ -55,6 +55,7 @@ matrix:
       env:
         - JOB=CARTHAGE-watchOS
     - script:
+      - gem install cocoapods --pre
       - pod repo update --silent
       - pod lib lint ReactiveObjC.podspec
       env:
