add pip retries. should help with github's occasional flaky network during build/test (#2506)

backend/Dockerfile

@@ -41,6 +41,8 @@ RUN apt-get update && \
 COPY ./requirements/default.txt /tmp/requirements.txt
 COPY ./requirements/ee.txt /tmp/ee-requirements.txt
 RUN pip install --no-cache-dir --upgrade \
+        --retries 5 \
+        --timeout 30 \
         -r /tmp/requirements.txt \
         -r /tmp/ee-requirements.txt && \
     pip uninstall -y py && \

backend/Dockerfile.model_server

@@ -15,7 +15,10 @@ ENV DANSWER_VERSION=${DANSWER_VERSION} \
 RUN echo "DANSWER_VERSION: ${DANSWER_VERSION}"
 
 COPY ./requirements/model_server.txt /tmp/requirements.txt
-RUN pip install --no-cache-dir --upgrade -r /tmp/requirements.txt
+RUN pip install --no-cache-dir --upgrade \
+        --retries 5 \
+        --timeout 30 \
+        -r /tmp/requirements.txt
 
 RUN apt-get remove -y --allow-remove-essential perl-base && \
     apt-get autoremove -y

backend/tests/integration/Dockerfile

@@ -31,6 +31,8 @@ RUN apt-get update && \
 COPY ./requirements/default.txt /tmp/requirements.txt
 COPY ./requirements/ee.txt /tmp/ee-requirements.txt
 RUN pip install --no-cache-dir --upgrade \
+        --retries 5 \
+        --timeout 30 \
         -r /tmp/requirements.txt \
         -r /tmp/ee-requirements.txt && \
     pip uninstall -y py && \