Only update packages indexes if the cache is 1 hour old

I have added cache_valid_time=3600 for the first task in each
tag that could be possibly running apt-related commands. For ex,
the "nginx" tag is also in the "packages" tag, but sometimes you
run the nginx tag by itself (perhaps repeatadely), so you'd want
to limit the update unless the cache was 1 hour old

roles/nginx/tasks/main.yml

@@ -8,7 +8,7 @@
   tags: nginx, packages
 
 - name: Install nginx
-  apt: pkg=nginx update_cache=yes state=latest
+  apt: pkg=nginx update_cache=yes state=latest cache_valid_time=3600
   tags: nginx, packages
 
 - name: Copy nginx configs