Set SKIP_VENV_SHELL_WARNING=1.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

Author: andersk

Dockerfile

@@ -39,7 +39,7 @@ WORKDIR /home/zulip/zulip
 ARG CUSTOM_CA_CERTIFICATES
 
 # Finally, we provision the development environment and build a release tarball
-RUN ./tools/provision --build-release-tarball-only
+RUN SKIP_VENV_SHELL_WARNING=1 ./tools/provision --build-release-tarball-only
 RUN . /srv/zulip-py3-venv/bin/activate && \
     ./tools/build-release-tarball docker && \
     mv /tmp/tmp.*/zulip-server-docker.tar.gz /tmp/zulip-server-docker.tar.gz