types: add optional release sequence field

[alisawavezen12]

Summary

Add an optional releaseSequence field to ReleaseDBScheme.

Purpose

releaseSequence will represent the order in which new releases are first registered in Hawk within a project. It will be used later by the release validator to determine the previous release when comparing event groups and assigning likelyFixed.

The sequence:

• starts at 1 for each project;
• is assigned only to new releases;
• remains unchanged when the same release is updated with additional commits or source maps;
• is not intended to represent the actual deployment time;
• may be absent on legacy releases created before this feature.

[neSpecc]

explain what is "release sequence" and why it is used

[alisawavezen12]

releaseSequence is a number for each project. It shows the order in which new releases were first saved in Hawk.

The release validator will use it to find the previous release and compare events between releases. We cannot use the release name or the RabbitMQ message order because release names can be arbitrary, and messages can arrive late or more than once.

The field is optional because old releases were created before this feature and do not have this value. For now, the number shows the order in which Hawk first received the releases, not the exact deployment order.