Typo in the README.md

In the README.md, in the instruction for installing aidge with pip, default_module_install.txt is spelled without the s:

# install full bundle
# - `aidge_core`
# - `aidge_backend_cpu`
# - `aidge_backend_cuda`
# - `aidge_backend_opencv`
# - `aidge_export_cpp`
# - `aidge_export_arm_cortexm`
# - `aidge_learning`
# - `aidge_onnx`
# - `aidge_quantization`
pip install -r default_module_intall.txt

# install selected modules, for example to import an ONNX, quantize the model and export it to a standalone CPP directory
pip install aidge-core aidge-backend-cpu aidge-learning aidge-export-cpp aidge-onnx aidge-quantization