The primary distribution channel for workerd right now is through npm. We use a (mostly) automatic CI setup to release and publish both workerd and workers-types.
workerd and workers-types follow the same versioning system. The major version is currently 1 for workerd and 4 for workers-types. The minor version for both is the compatibility date specified in supported-compatibility-date.txt (the latest compatibility date that the workerd release will support).
This is pretty simple, and completely automatic—every time the compatibility date in supported-compatibility-date.txt changes, a new release is generated, along with the built binaries for linux-64, linux-arm64, darwin-64, darwin-arm64 and windows-64. The types will also be generated and published automatically. This is governed by the release.yml GitHub Action.