certbot: restore compatibility with old Nginx

CHANGELOG.md

@@ -27,6 +27,8 @@ The **patch** part changes incrementally at each release.
 
 ### Fixed
 
+* certbot: restore compatibility with old Nginx
+
 ### Removed
 
 ### Security

certbot/templates/acme-challenge/nginx.conf.j2

@@ -1,5 +1,9 @@
 location ~ /.well-known/acme-challenge {
+{% if ansible_distribution == "Debian" and ansible_distribution_major_version is version('8', '<=') %}
+    alias {{ certbot_work_dir }}/.well-known/acme-challenge;
+{% else %}
     alias {{ certbot_work_dir }}/;
+{% endif %}
     try_files $uri =404;
     allow all;
 }