Issue
You are trying to create a one-off dyno in a Shield space and are getting an error after upgrading to Mac OS Ventura.
CLIError: There was a problem connecting to the dyno.
Confirm that your ssh key is added to your agent by running `ssh-add`.
Check that your ssh key has been uploaded to heroku with `heroku keys:add`.
See https://devcenter.heroku.com/articles/one-off-dynos#shield-private-spaces
Resolution
Mac OS Ventura utilizes the recent update of OpenSSH 9 which disables RSA signatures using the SHA-1 hash algorithm.
You will need to generate new keys with a more secure algorithm such as ED25519 or ECDSA.
Run ssh-keygen -o -a 100 -t ed25519 -f ~/.ssh/id_ed25519
And then run heroku keys:add and select the id_ed25519.pub file.