This ensures that we exercise the fact that the Zulip installer may be
unpacked to a directory that may not be world-readable.
bc45525369 fixed a recent regression in
this behavior that would have been caught by this commit.
We have disabled CircleCI and are using GitHub Actions for automated
testing.
docs: Changed context from CircleCI to Github Actions and wrote
some documentation specific to GH Actions.
tools: Replaced env checks for CIRCLECI with GITHUB_ACTION.
README: Use GitHub Actions build status badge.
Run production suites on Ubuntu Focal.
Added separate success-http-headers files for Focal and Bionic.
Also excluded them from whitespace rules in lint.
memcached 1.5.22 in Ubuntu 20.04 has a bug where it looks for its SASL
configuration at /etc/sasl2/memcached.conf/memcached.conf instead of
/etc/sasl2/memcached.conf.
We already use a workaround for this while applying puppet configurations in
99e71f3786 but for docker builds we used
do memcached hack since we can not use systemd in docker containers.