Remove pinning protobuf version since 3.20.3 is old and not supported by Tensorflow

Install `tf_nightly[and_cuda]` for Keras GPU builds.

PiperOrigin-RevId: 728362609

Author: tensorflower-gardener

requirements.txt

@@ -8,8 +8,8 @@ scipy
 # with both new and old protobuf stubs. This is needed to resolve
 # Keras-TensorFlow circular dependency issue, when one of them gets a dependency
 # incompatible with another one (protobuf in this specific case).
-protobuf==3.20.3
-tf-nightly
+protobuf==4.21.6
+tf-nightly[and_cuda]
 portpicker
 pyyaml
 Pillow

tf_keras/kokoro/github/ubuntu/gpu/build.sh

@@ -42,7 +42,7 @@ pip uninstall -y keras-nightly
 
 # LD Library Path needs to be same as TensorFlow Ubuntu Docker build -
 # https://github.com/tensorflow/tensorflow/blob/master/tensorflow/tools/tf_sig_build_dockerfiles/
-export LD_LIBRARY_PATH="/usr/local/cuda/lib64:/usr/local/cuda/extras/CUPTI/lib64:/usr/local/tensorrt/lib"
+# export LD_LIBRARY_PATH="/usr/local/cuda/lib64:/usr/local/cuda/extras/CUPTI/lib64:/usr/local/tensorrt/lib"
 CUDA_TOOLKIT_PATH="/usr/local/cuda-11.8"
 TF_CUDA_CONFIG_REPO="@ubuntu20.04-gcc9_manylinux2014-cuda11.8-cudnn8.6-tensorrt8.4_config_cuda"
 TF_CUDA_COMPUTE_CAPABILITIES="sm_35,sm_50,sm_60,sm_70,sm_75,compute_80"