fixed typing in the datapoint test

tests/test_datapoint.py

@@ -4,8 +4,8 @@ test_dict = {
     "timestamp": int(time.time()),
     "tag_1key": "tag_1value",
     "tag_2key": "tag_2value",
-    "field_1key": "field_1value",
-    "field_2key": "field_2value",
+    "field_1key": 1.2,
+    "field_2key": 2,
     "neither_1key": "neither_1value",
 }