[BUG]: drizzle-kit foreign key names changed from _fk to _fkey suffix

### Report hasn't been filed before.

- [x] I have verified that the bug I'm about to report hasn't been filed before.

### What version of `drizzle-orm` are you using?

1.0.0-beta.6

### What version of `drizzle-kit` are you using?

1.0.0-beta.6-4414a19

### Other packages

_No response_

### Describe the Bug

When generating migrations including foreign key constraints, drizzle-kit now uses a `_fkey` suffix for the constraint name. Previously it was using a `_fk` suffix. This is problematic for dropping/renaming existing foreign keys created by Drizzle using the `_fk` name convention. Ideally it would just stick with `_fk` for backwards compatibility (plus personally I find the `_fk` naming more idiomatic than `_fkey`).