Accept logs without upstream timing

tests/test_main.py

@@ -10,6 +10,13 @@ def test_parse_line_and_multiple_upstreams():
     assert event["upstream_time"] == 0.15
 
 
+def test_parse_line_with_empty_trailing_upstream_time():
+    event = parse_line("1720000000.123 example.test GET 200 120 240 0.150")
+    assert event is not None
+    assert event["host"] == "example.test"
+    assert event["upstream_time"] is None
+
+
 def test_malformed_lines_are_ignored():
     assert parse_line("not enough fields") is None
     assert parse_line("1 host GET nope 1 2 0.1 -") is None