Improve Dockerfile to cache pip dependency

src/ainu_lm_trainer/Dockerfile

@@ -5,13 +5,18 @@ ARG HF_TOKEN
 ENV TRANSFORMERS_NO_ADVISORY_WARNINGS=1
 
 RUN apt update
-COPY . /workspace
 
-RUN pip install poetry
-RUN poetry config virtualenvs.create false
-RUN poetry export -f requirements.txt --output requirements.txt
+COPY pyproject.toml poetry.lock /workspace/
+
+RUN pip install poetry \
+ && poetry config virtualenvs.create false \
+ && poetry export -f requirements.txt --output requirements.txt --without-hashes \
+ && pip uninstall -y poetry
+
 RUN pip install -r requirements.txt
 
+COPY . /workspace
+
 RUN python3 -m src.ainu_lm_trainer.app.main cache
 
 ENTRYPOINT ["python3", "-m", "src.ainu_lm_trainer.app.main"]