- Updated to 1.21.0
* https://nginx.org/en/CHANGES
* Added variables support in the "proxy_ssl_certificate",
"proxy_ssl_certificate_key" "grpc_ssl_certificate",
"grpc_ssl_certificate_key", "uwsgi_ssl_certificate", and
"uwsgi_ssl_certificate_key" directives.
* Added the "max_errors" directive in the mail proxy module.
* Added the mail proxy module supports POP3 and IMAP pipelining.
* Added the "fastopen" parameter of the "listen" directive in the
stream module.
* Fixed special characters were not escaped during automatic redirect
with appended trailing slash.
* Fixed connections with clients in the mail proxy module might be
closed unexpectedly when using SMTP pipelining.