fix dockerfile

Dockerfile

@@ -126,10 +126,13 @@ WORKDIR /
 COPY models/tacotron2 ./models/tacotron2
 WORKDIR models/tacotron2
 
-RUN python3.8 -m venv python
+# NB: Not sure if we need Python3.6 for Tacotron2, but Python3.8 gave me trouble.
+# NB: Setuputils fix: https://github.com/tensorflow/tensorflow/issues/34302#issuecomment-554450289
+RUN python3.6 -m venv python
 RUN . python/bin/activate \
   && pip install --upgrade pip \
-  && pip install -r requirements.txt \
+  && python -m pip install --upgrade pip setuptools
+  && pip install -r requirements-working-2021-05-31.txt \
   && deactivate
 
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