Rename pubkey to loginPubkey because we'll soon have another pubkey.

This breaks sharing because we no longer have a normal pubkey.
This will be fixed in the next commit.

django_etesync/migrations/0005_auto_20200526_1021.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.0.3 on 2020-05-26 10:21
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_etesync', '0004_collectioninvitation_version'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='userinfo',
+            old_name='pubkey',
+            new_name='loginPubkey',
+        ),
+    ]