make prod stream opened field editable by factory

scipost_django/production/migrations/0010_alter_productionstream_opened.py

+# Generated by Django 3.2.18 on 2023-10-06 15:27
+
+from django.db import migrations, models
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('production', '0009_productionstream_on_hold'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='productionstream',
+            name='opened',
+            field=models.DateTimeField(default=django.utils.timezone.now),
+        ),
+    ]

scipost_django/production/models.py

@@ -73,7 +73,7 @@ class ProductionStream(models.Model):
         on_delete=models.CASCADE,
         related_name="production_stream",
     )
-    opened = models.DateTimeField(auto_now_add=True)
+    opened = models.DateTimeField(default=timezone.now)
     closed = models.DateTimeField(default=timezone.now)
     status = models.CharField(
         max_length=32,