fixes for #10070 make l2vpn slug unique (#10119)

Co-authored-by: jeremystretch <jstretch@ns1.com>

netbox/ipam/migrations/0060_alter_l2vpn_slug.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.0.7 on 2022-08-22 15:58
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('ipam', '0059_l2vpn'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='l2vpn',
+            name='slug',
+            field=models.SlugField(max_length=100, unique=True),
+        ),
+    ]