sqlx-cli requires --database-url parameter

[tvallotton]

Hi, I forked the project and I noticed that now in order to run migrations this was a requirement, even if I have DATABASE_URL set in my .env. If that was intentional then just close this issue.

[abonander]

This was a bug recently introduced that we just merged a fix for in #1432

[fenhl]

It seems that this issue has reappeared in version 0.6.3.