.exports: Hide zsh warning on macOS

Author: mathiasbynens

.exports

@@ -32,3 +32,6 @@ export MANPAGER='less -X';
 # Avoid issues with `gpg` as installed via Homebrew.
 # https://stackoverflow.com/a/42265848/96656
 export GPG_TTY=$(tty);
+
+# Hide the “default interactive shell is now zsh” warning on macOS.
+export BASH_SILENCE_DEPRECATION_WARNING=1;