Hyper doesn't use default shell on MacOS

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate

• OS version and name: macOS Catalina (10.15.3)
• Hyper.app version: 3.0.2
• Link of a Gist with the contents of your .hyper.js: https://gist.github.com/kevtan/676534f30a79f7d816254b7af515aefe
• Relevant information from devtools (CMD+ALT+I on macOS, CTRL+SHIFT+I elsewhere): N/A
• The issue is reproducible in vanilla Hyper.app: Is Vanilla

Issue

Right out of the box, on macOS, Hyper still uses bash instead of the system default (which is now zsh). This causes the following annoying message to appear:

The default interactive shell is now zsh.
To update your account to use zsh, please run `chsh -s /bin/zsh`.
For more details, please visit https://support.apple.com/kb/HT208050.

Running the suggested command chsh -s /bin/zsh does nothing because it just changes the default system shell... which is already zsh! The issue is that Hyper is launching the bash shell by default, even though this isn't the system default. It can be easily fixed by changing the shell field in .hyper.js to be "/bin/zsh" but it would be nice if this worked out of the box!

Start with the .hyper.js shell setting and reproduce the launch behavior on macOS with zsh configured as the system default. Trace how Hyper chooses its shell, then verify a vanilla Hyper.app session uses the system default without showing the bash-to-zsh warning.