Changed my_first_attribute data_type to ASCII_Real

Per bug identified by @johndoe, this change will update my_first_attribute to use the ASCII_Real data type.

Resolves pds-data-dictionaries/PDS4-LDD-Issue-Repo#13

src/PDS4_EXAMPLE_IngestLDD.xml

@@ -23,7 +23,7 @@
     </definition>
     <DD_Value_Domain>
       <enumeration_flag>false</enumeration_flag>
-      <value_data_type>ASCII_Integer</value_data_type>
+      <value_data_type>ASCII_Real</value_data_type>
       <unit_of_measure_type>Units_of_None</unit_of_measure_type>
     </DD_Value_Domain>
   </DD_Attribute>