[serialization_lib] Add tosa shape ops

Added tosa shape ops to tosa.fbs
also added convert I64 to and from U8 for storing const_shape data values

Signed-off-by: Tai Ly <tai.ly@arm.com>
Change-Id: I1e938dec7398fbcbe5be657dad65cdd61af5b597
diff --git a/.gitignore b/.gitignore
index ba0430d..5034363 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
-__pycache__/
\ No newline at end of file
+__pycache__/
+build/
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