test: use a valid precision (38) in TEST_PRIMITIVE_TYPES

DecimalType(100, 2) exceeds the spec's max precision of 38 and is now rejected
by the new validation; use the maximum valid precision instead.

Author: kratos0718

tests/test_schema.py

@@ -67,7 +67,7 @@
     FloatType(),
     DoubleType(),
     DecimalType(10, 2),
-    DecimalType(100, 2),
+    DecimalType(38, 2),
     StringType(),
     DateType(),
     TimeType(),