fix: corrects download URL for rules files (#494)

Author: andreyev

rules.md

@@ -64,7 +64,7 @@
         {% else %}
 {{ exporter.comments | strip | newline_to_br }}
 {% highlight bash %}
-$ wget https://raw.githubusercontent.com/samber/awesome-prometheus-alerts/ref/head/dist/rules/{{ service.name | replace: " ", "-" | downcase }}/{{ exporter.slug }}.yml
+$ wget https://raw.githubusercontent.com/samber/awesome-prometheus-alerts/refs/heads/master/dist/rules/{{ service.name | replace: " ", "-" | downcase }}/{{ exporter.slug }}.yml
 {% endhighlight %}
         {% endif %}