[CI] Use update instead of install to gem

norio-nomura · norio-nomura · commit 7a7e67d15d3d · 2019-03-07T21:37:33.000+09:00
diff --git a/.travis.yml b/.travis.yml
@@ -8,7 +8,7 @@ aliases:
   - &cocoapods
     script:
       - rm .swift-version
-      - gem install cocoapods
+      - gem update cocoapods
       - pod repo update master
       - pod lib lint --verbose
     os: osx
