Merge pull request #4268 from pks-t/pks/homebrew-dupes-deprecation

travis: replace use of deprecated homebrew/dupes tap
diff --git a/script/install-deps-osx.sh b/script/install-deps-osx.sh
index 27d8096..94314db 100755
--- a/script/install-deps-osx.sh
+++ b/script/install-deps-osx.sh
@@ -3,7 +3,7 @@
 set -x
 
 brew update
-brew install homebrew/dupes/zlib
+brew install zlib
 brew install curl
 brew install openssl
 brew install libssh2