Add `:ssl` to `extra_applications`

[jdav-dev]

Ensure :ssl is started before Commanded.Middleware.Auditing.Repo.

[jdav-dev]

Hi :wave:

I opened this PR because commanded_audit_middleware seemed to be starting before ssl and would therefore crash when connecting to the DB. ssl was already present in our own application's extra_applications and wasn't doing the trick. Adding it to commanded_audit_middleware's extra_applications got us working.

Is this the appropriate fix? Is there a better way? I'd like to get this merged unless there's a better way.

Thanks!