v0.23.0

### Added

- Added full support for AMD CPUs (General Availability). More details [here](README.md#supported-platforms).
- Added snapshot-restore functionality (Developer preview). More details [here](docs/snapshotting/snapshot-support.md).
- Added metric for throttled block device events.
- Added metrics for counting rate limiter throttling events.
- Added metric for counting MAC address updates.
- Added metrics for counting TAP read and write errors.
- Added metrics for counting RX and TX partial writes.
- Added metrics that measure the duration of pausing and resuming the microVM,
  from the VMM perspective.
- Added metric for measuring the duration of the last full snapshot created,
  from the VMM perspective.
- Added metric for measuring the duration of loading a snapshot, from the VMM
  perspective.
- Added metrics that measure the duration of pausing and resuming the microVM,
  from the API (user) perspective.
- Added metric for measuring the duration of the last full snapshot created,
  from the API (user) perspective.
- Added metric for measuring the duration of loading a snapshot, from the API
  (user) perspective.
- Added `track_dirty_pages` field to `machine-config`. If enabled, Firecracker
  can create incremental guest memory snapshots by saving the dirty guest pages
  in a sparse file.
- Added a new API call, `PATCH /vm`, for changing the microVM state (to
  `Paused` or `Resumed`).
- Added a new API call, `PUT /snapshot/create`, for creating a full snapshot.
- Added a new API call, `PUT /snapshot/load`, for loading a snapshot.
- Added new jailer command line argument `--cgroup` which allow the user to
  specify the cgroups that are going to be set by the Jailer.

### Fixed

- Boot time on AMD achieves the desired performance (i.e under 150ms).

### Changed

- The logger `level` field is now case-insensitive.
- Disabled boot timer device after restoring a snapshot.
- Enabled boot timer device only when specifically requested, by using the
  `--boot-timer` dedicated cmdline parameter.
- firecracker and jailer `--version` now gets updated on each devtool
  build to the output of `git describe --dirty`, if the git repo is available.
- MicroVM process is only attached to the cgroups defined by using `--cgroups`
  or the ones defined indirectly by using `--node`.