Added the const qualifier to char* variables that refer to readonly internal
UTF-8 represenatation of Unicode objects.
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 5937520..71245c2 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -3613,7 +3613,7 @@
 
     for (i = 0; i < PySequence_Size(events_seq); ++i) {
         PyObject *event_name_obj = PySequence_Fast_GET_ITEM(events_seq, i);
-        char *event_name = NULL;
+        const char *event_name = NULL;
         if (PyUnicode_Check(event_name_obj)) {
             event_name = PyUnicode_AsUTF8(event_name_obj);
         } else if (PyBytes_Check(event_name_obj)) {