Update tfnightly to 2.18.0.dev20240806

Change-Id: Ieba2a0c4f7e2031eb23daf317005f3102b44ece3
diff --git a/python-requirements.txt b/python-requirements.txt
index 68cbf59..c4ba13e 100644
--- a/python-requirements.txt
+++ b/python-requirements.txt
@@ -44,6 +44,6 @@
 scipy
 sel4-deps
 setuptools
-tf-nightly==2.17.0.dev20240507
+tf-nightly==2.18.0.dev20240806
 wget
 yapf