fix: don’t require url in license admin view

program/migrations/0069_alter_license_url.py

+# Generated by Django 4.2.2 on 2023-08-30 14:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("program", "0068_license_needs_author_and_more"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="license",
+            name="url",
+            field=models.URLField(blank=True, default=""),
+        ),
+    ]

program/models.py

@@ -118,7 +118,7 @@ class License(models.Model):
     name = models.CharField(max_length=64, help_text="Name of the license")
     needs_author = models.BooleanField(default=True)
     requires_express_permission_for_publication = models.BooleanField(default=True)
-    url = models.URLField(default="")
+    url = models.URLField(default="", blank=True)
 
     class Meta:
         ordering = ("name",)