allow DL3064

```
ci_build_images/minio.fragment.Dockerfile:18 DL3064 warning: Potentially sensitive data should not be used in the `ARG` or `ENV` commands
```

There's nothing sensitive there, the MINIO_ROOT_PASSWORD is not the one
used for the public facing S3 service, but for the local minio of that container.

Author: RazvanLiviuVarzaru

.hadolint.yaml

@@ -10,6 +10,7 @@ ignored:
   - DL3037
   - DL3041
   - DL3061
+  - DL3064
   - DL3066
   - DL4006
   - SC1091