Reduce the cache-control time to 60s

The WP-Supercache Apache caching will anyway cover NGINX
requests for 300s.

docker/conf/cont-init.d/50cache-htaccess

@@ -7,9 +7,9 @@ if [ ! -e "$cache_dir/.htaccess" ]; then
     cat >"$cache_dir/.htaccess" <<EOF
 Options -Indexes
 Header set Vary "Accept-Encoding, Cookie"
-Header set Cache-Control "max-age=300"
+Header set Cache-Control "max-age=60"
 ExpiresActive On
-ExpiresByType text/html A300
+ExpiresByType text/html A60
 EOF
 fi