update .gitignore

hc

2024-03-26 e9199a72d842cbda78ac614eee5db7cdaa6f2530

external/rknpu2/examples/3rdparty/opencv/OpenCV-android-sdk/sdk/native/3rdparty/libs/arm64-v8a/liblibprotobuf.a does not exist in tree c129e61995bb24041cc70f65154ed02c40ec3e8a