Purge the Fastly CDN in Github Actions, when deploying new code.
I am also investigating an issue related to this topic, and have started
a discussion with them. The TTL of css/styles.css is set to 1 hr in the
console. Sometimes it flips back to use the "cache-control:
max-age=604800" sent by the Django webserver. Not every time though.
There are many fastly cache servers, and hierarchical, could be related
to that.
