Fix fetch_models.sh in examples. (#8434)

Author: mc-nv

docs/examples/fetch_models.sh

@@ -33,9 +33,11 @@ mkdir -p model_repository/inception_onnx/1
 wget -O /tmp/inception_v3_2016_08_28_frozen.pb.tar.gz \
      https://storage.googleapis.com/download.tensorflow.org/models/inception_v3_2016_08_28_frozen.pb.tar.gz
 (cd /tmp && tar xzf inception_v3_2016_08_28_frozen.pb.tar.gz)
+apt update -qq && apt install -y python3-venv
+rm -rf tf2onnx
 python3 -m venv tf2onnx
 source ./tf2onnx/bin/activate
-pip3 install "numpy<2" tensorflow tf2onnx
+pip3 install "numpy<2" tensorflow==2.18.1 tf2onnx==1.16.1 onnx==1.16.1
 python3 -m tf2onnx.convert --graphdef /tmp/inception_v3_2016_08_28_frozen.pb --output inception_v3_onnx.model.onnx --inputs input:0 --outputs InceptionV3/Predictions/Softmax:0
 deactivate
 mv inception_v3_onnx.model.onnx model_repository/inception_onnx/1/model.onnx