.build.yml: update to Alpine 3.13
align annotations with actual thresholds
Bump weekly test alarm to urgent
Fix typo in password reset alarm
I/O alarm: correct error for write metric
Loosen alarm for login failures

This is a bit too noisy
Fix high CPU usage alert
Add alarm for aging ZFS snapshots
Add an alert for high rate of server errors
.build.yml: switch to Alpine 3.12
add urgent alarm for sustained login failure rate
Improve CPU utilization rules
Re-introduce test alarm
Bump disk usage alarms to 90%
Fix builds.sr.ht alerts

According to prometheus documentation, delta should only be used with
gauges and increase can be used with counters.

This changes the threshold for high rate of build submissions from 25
per second to 25 per 5 minutes. According to the metrics.sr.ht data, a
threshold of 20 build submissions per 5 minutes was never exceeded.
Fix read-only filesystem alert
Revert "Fix read-only filesystem alert"

This reverts commit 4472e54ccd444a65697a3680a03071307c91292b.
Fix read-only filesystem alert
Remove test_rules.yml

This doesn't work the way I expected it to
Make test rules more explicit to appease prometheus
Add test_rules.yml