bpo-39943: Add the const qualifier to pointers on non-mutable PyUnicode data. (GH-19345)

diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index 697295d..92bdfe3 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -1644,7 +1644,7 @@
     const char *uppercase_name_str;
     int rc;
     unsigned int kind;
-    void *data;
+    const void *data;
 
     if (!pysqlite_check_thread(self) || !pysqlite_check_connection(self)) {
         goto finally;