XSLT fix changed by

src/objects/zcl_abapgit_object_xslt.clas.abap

@@ -19,7 +19,25 @@ CLASS zcl_abapgit_object_xslt IMPLEMENTATION.
   ENDMETHOD.  "zif_abapgit_object~has_changed_since
 
   METHOD zif_abapgit_object~changed_by.
-    rv_user = c_user_unknown. " todo
+
+    DATA: lo_xslt       TYPE REF TO cl_o2_api_xsltdesc,
+          ls_attributes TYPE o2xsltattr.
+
+    lo_xslt = get( ).
+    lo_xslt->get_attributes(
+      RECEIVING
+        p_attributes     = ls_attributes
+      EXCEPTIONS
+        object_invalid   = 1
+        xsltdesc_deleted = 2
+        OTHERS           = 3 ).
+
+    IF sy-subrc <> 0.
+      zcx_abapgit_exception=>raise_t100( ).
+    ENDIF.
+
+    rv_user = ls_attributes-changedby.
+
   ENDMETHOD.
 
   METHOD get.