Use git refs for pushes

Signed-off-by: mueller-ma <[email protected]>

.travis.yml

@@ -53,7 +53,7 @@ before_deploy:
 - git config --local user.email "[email protected]"
 - git add fastlane/*
 - git commit -m "Update fastlane metadata"
-- git push origin master
+- git push origin :refs/heads/master
 - openssl aes-256-cbc -K $encrypted_903a93ed2309_key -iv $encrypted_903a93ed2309_iv
   -in keystore.enc -out keystore -d
 - cp $TRAVIS_BUILD_DIR/keystore $HOME