Getting error when using civix generate:module or civix generate:entity curly braces no longer supported in phar
UPDATE 2: The PR was merged so now the latest civix phar download supports php 7.4 (insert emoji yay! here)

UPDATE: PR submitted to update civix to update its version of cv: https://github.com/totten/civix/pull/200

Are you on php 7.4? You have an old version of cv within your civix phar. I'd download a new copy of civix.
i.e. https://github.com/civicrm/cv/commit/018c667429653ca06bc1dff6a93fdec87d9171bc