Fix numpy, scipy and PIL deps in unittests (#3932)

Author: NicolasHug

.github/scripts/unittest-linux/install.sh

@@ -97,6 +97,9 @@ fi
     set -x
     conda install -y -c conda-forge ${NUMBA_DEV_CHANNEL} sox libvorbis librosa parameterized 'requests>=2.20' 'ffmpeg>=6,<7'
     pip install kaldi-io SoundFile coverage pytest pytest-cov scipy expecttest unidecode inflect Pillow sentencepiece pytorch-lightning 'protobuf<4.21.0' demucs tinytag pyroomacoustics flashlight-text git+https://github.com/kpu/kenlm
+
+    # TODO: might be better to fix the single call to `pip install` above
+    pip install "pillow<10.0" "scipy<1.10" "numpy<2.0"
 )
 # Install fairseq
 git clone https://github.com/pytorch/fairseq