Update tensorflow to 2.14 in requirements.txt

Change-Id: I058e80a1c6aec1451255104ec5f5210ab436240b
Signed-off-by: Jonny Svärd <jonny.svaerd@arm.com>
diff --git a/requirements.txt b/requirements.txt
index 57f9897..0a2d9fc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
 ethos-u-vela
 pillow
 pyelftools
-tensorflow==2.12
+tensorflow==2.14