Security update nginx from 1.17.2 to 1.17.3.
<ChangeLog with nginx 1.17.3>
*) Security: when using HTTP/2 a client might cause excessive memory
consumption and CPU usage (CVE-2019-9511, CVE-2019-9513, CVE-2019-9516).
*) Bugfix: "zero size buf" alerts might appear in logs when using
gzipping; the bug had appeared in 1.17.2.
*) Bugfix: a segmentation fault might occur in a worker process if the
"resolver" directive was used in SMTP proxy.