Set the working git-tag for Gemma.cpp

- gemma.cpp origin/main has been updated and the changes were not
backcompatible with the current bindings
- this is a short term fix that sets the git-tag to the first gemma.cpp
commit resulting in a version that compiles without errors
- TODO: update bindings to support the new interface and spec for libgemma

Author: pagakarthik

CMakeLists.txt

@@ -11,7 +11,7 @@ set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 FetchContent_Declare(sentencepiece GIT_REPOSITORY https://github.com/google/sentencepiece GIT_TAG 53de76561cfc149d3c01037f0595669ad32a5e7c)
 FetchContent_MakeAvailable(sentencepiece)
 
-FetchContent_Declare(gemma GIT_REPOSITORY https://github.com/google/gemma.cpp GIT_TAG origin/main)
+FetchContent_Declare(gemma GIT_REPOSITORY https://github.com/google/gemma.cpp GIT_TAG e29cd566cf3367671e8f59419a04e308796a7c57)
 FetchContent_MakeAvailable(gemma)
 
 FetchContent_Declare(highway GIT_REPOSITORY https://github.com/google/highway.git GIT_TAG da250571a45826b21eebbddc1e50d0c1137dee5f)