fixed parsing of trailing comma and pkg

Author: Phelsong

dist/mojo_csv.mojopkg

@@ -93,6 +93,9 @@ struct CsvReader[]:
                 if pos + 1 < self.length:
                     self.row_count += 1
                     col_start = pos + 1
+            
+            elif pos == self.length:
+                self.elements.append(self.raw[col_start:pos])
             # -------
         # -------------
 

src/csv_reader.mojo

@@ -1,3 +1,3 @@
 item1,item2,"ite,em3"
 pic, pi c,pic,
-r_i_1,r_i_2,r_i_3,
+r_i_1,r_i_2,r_i_3,