Change purchased_from options so supplier deletion does not delete assets

assets/migrations/0023_alter_asset_purchased_from.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.12 on 2022-02-14 15:13
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('assets', '0022_alter_cabletype_unique_together'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='asset',
+            name='purchased_from',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, related_name='assets', to='assets.supplier'),
+        ),
+    ]