Bump nginx to v1.21.3 (#26)

Author: levonet

Dockerfile

@@ -1,6 +1,6 @@
 FROM alpine:3.14 AS build
 
-ENV NGINX_VERSION 1.21.2
+ENV NGINX_VERSION 1.21.3
 # https://github.com/nginx/njs
 ENV NJS_MODULE_VERSION 0.6.2
 # https://github.com/openresty/echo-nginx-module

README.md

@@ -1,7 +1,7 @@
 # Supported tags and respective `Dockerfile` links
 
 - [`latest` (*Dockerfile*)](https://github.com/levonet/docker-nginx/blob/master/Dockerfile)
-- [`1.21.2-alpine`, `1.21-alpine` (*Dockerfile*)](https://github.com/levonet/docker-nginx/blob/v1.21.2/Dockerfile) Mainline version
+- [`1.21.3-alpine`, `1.21-alpine` (*Dockerfile*)](https://github.com/levonet/docker-nginx/blob/v1.21.3/Dockerfile) Mainline version
 - [`1.20.1-alpine`, `1.20-alpine` (*Dockerfile*)](https://github.com/levonet/docker-nginx/blob/v1.20.1/Dockerfile) Stable version
 - <details><summary>Older versions</summary>