Update Dockerfile.windows (#1414)

Fixes this error:
Poetry could not find a pyproject.toml file in C:\app or its parents

When running this command:
docker build . -f Dockerfile.windows -t presidio-analyzer --platform=windows/amd64

presidio-analyzer/Dockerfile.windows

@@ -17,7 +17,7 @@ COPY ${NLP_CONF_FILE} /usr/bin/${NAME}/${NLP_CONF_FILE}
 ADD https://aka.ms/vs/16/release/vc_redist.x64.exe .
 RUN ./vc_redist.x64.exe /quiet /install
 
-COPY ./pyproject.toml /usr/bin/${NAME}/
+COPY ./pyproject.toml /app/pyproject.toml
 COPY ./README.md /usr/bin/${NAME}/
 RUN pip install --upgrade pip
 RUN pip install poetry; poetry install --no-root --only=main -E server -E transformers