fix: fix incorrect file extension casing in integration test

Author: isc-shuliu

tests/integration_tests/Test/PM/Integration/_data/cpf-merge/module.xml

@@ -5,9 +5,9 @@
       <Name>cpf-merge</Name>
       <Version>0.0.1</Version>
       <Packaging>module</Packaging>
-      <CPF Name="config-globals.CPF"/>
-      <CPF Name="create-roles.CPF" Directory="custom-cpf-directory"/>
-      <CPF Name="package-mapping.CPF"/>
+      <CPF Name="config-globals.cpf"/>
+      <CPF Name="create-roles.cpf" Directory="custom-cpf-directory"/>
+      <CPF Name="package-mapping.cpf"/>
     </Module>
   </Document>
 </Export>