changelog: Update new commands available in snapshot-editor

Update CHANGELOG to publish addition of new command to print
MicrovmState from vmstate snapshot files and that vcpu-states
is now available on X86_64 as well.

Signed-off-by: Sudan Landge <[email protected]>

Author: Sudan Landge

CHANGELOG.md

@@ -9,6 +9,11 @@
   each individual net device will emit metrics under the label `"net_{iface_id}"`.
   E.g. the associated metrics for the endpoint `"/network-interfaces/eth0"` will
   be available under `"net_eth0"` in the metrics json object.
+- [#4205](https://github.com/firecracker-microvm/firecracker/pull/4205):
+  Added a new `vm-state` subcommand to `info-vmstate` command in the
+  `snapshot-editor` tool to print MicrovmState of vmstate snapshot file in
+  a readable format. Also made the `vcpu-states` subcommand available on
+  x86_64.
 
 ### Changed