feat: pass --assume-in-transaction to squawk

Alembic migrations always run inside a transaction by default, so squawk
should always be told to assume that context.

Author: stephen-kintsugi

squawk_alembic/hook.py

@@ -220,7 +220,7 @@ def main():
 
         try:
             result = subprocess.run(
-                ["squawk", tmp_path],
+                ["squawk", "--assume-in-transaction", tmp_path],
                 capture_output=True,
                 text=True,
             )

tests/test_main.py

@@ -99,6 +99,7 @@ def upgrade():
         assert "def456:abc123" in alembic_call
         squawk_call = mock_run.call_args_list[1][0][0]
         assert squawk_call[0] == "squawk"
+        assert "--assume-in-transaction" in squawk_call
 
 
 def test_squawk_failure(repo, capsys):