Updated Nginx Proxy Manager to version 2.9.21.

Author: jlesage

Dockerfile

@@ -9,7 +9,7 @@ ARG DOCKER_IMAGE_VERSION=
 
 # Define software versions.
 ARG OPENRESTY_VERSION=1.19.9.1
-ARG NGINX_PROXY_MANAGER_VERSION=2.9.20
+ARG NGINX_PROXY_MANAGER_VERSION=2.9.21
 ARG NGINX_HTTP_GEOIP2_MODULE_VERSION=3.3
 ARG LIBMAXMINDDB_VERSION=1.5.0
 ARG BCRYPT_TOOL_VERSION=1.1.2