Use NUM2INT instead of FIX2INT for timestamp conversion

NUM2INT is more robust as it handles both Fixnum and Bignum,
while FIX2INT only works with Fixnum.

Author: suketa

ext/duckdb/scalar_function.c

@@ -266,13 +266,13 @@ static void vector_set_value_at(duckdb_vector vector, duckdb_logical_type elemen
             }
 
             duckdb_timestamp_struct ts_struct;
-            ts_struct.date.year = FIX2INT(rb_funcall(value, rb_intern("year"), 0));
-            ts_struct.date.month = FIX2INT(rb_funcall(value, rb_intern("month"), 0));
-            ts_struct.date.day = FIX2INT(rb_funcall(value, rb_intern("day"), 0));
-            ts_struct.time.hour = FIX2INT(rb_funcall(value, rb_intern("hour"), 0));
-            ts_struct.time.min = FIX2INT(rb_funcall(value, rb_intern("min"), 0));
-            ts_struct.time.sec = FIX2INT(rb_funcall(value, rb_intern("sec"), 0));
-            ts_struct.time.micros = FIX2INT(rb_funcall(value, rb_intern("usec"), 0));
+            ts_struct.date.year = NUM2INT(rb_funcall(value, rb_intern("year"), 0));
+            ts_struct.date.month = NUM2INT(rb_funcall(value, rb_intern("month"), 0));
+            ts_struct.date.day = NUM2INT(rb_funcall(value, rb_intern("day"), 0));
+            ts_struct.time.hour = NUM2INT(rb_funcall(value, rb_intern("hour"), 0));
+            ts_struct.time.min = NUM2INT(rb_funcall(value, rb_intern("min"), 0));
+            ts_struct.time.sec = NUM2INT(rb_funcall(value, rb_intern("sec"), 0));
+            ts_struct.time.micros = NUM2INT(rb_funcall(value, rb_intern("usec"), 0));
 
             duckdb_timestamp ts = duckdb_to_timestamp(ts_struct);
             ((duckdb_timestamp *)vector_data)[index] = ts;