fix: use true UUID type for Upgrades table primary key

hopefully can use this everywhere soon but let's start slow and test

tests/test_app.py

@@ -5,6 +5,7 @@ import shutil
 import sys
 import tempfile
 import warnings
+import uuid as _uuid
 from unittest import TestCase
 from unittest.mock import patch, MagicMock
 
@@ -385,6 +386,10 @@ app_title = WuttaTest
         uuid = self.app.make_uuid()
         self.assertEqual(len(uuid), 32)
 
+    def test_make_true_uuid(self):
+        uuid = self.app.make_true_uuid()
+        self.assertIsInstance(uuid, _uuid.UUID)
+
     def test_progress_loop(self):
 
         def act(obj, i):