update changelog (new upstream snapshot)

debian/changelog

@@ -1,4 +1,4 @@
-cloud-init (24.2-0ubuntu1~20.04.2) UNRELEASED; urgency=medium
+cloud-init (24.3.1-0ubuntu0~20.04.1) UNRELEASED; urgency=medium
 
   * d/p/no-nocloud-network.patch: Remove nocloud network feature
   * d/p/no-single-process.patch: Remove single process optimization
@@ -7,8 +7,12 @@ cloud-init (24.2-0ubuntu1~20.04.2) UNRELEASED; urgency=medium
     - d/p/cli-retain-file-argument-as-main-cmd-arg.patch
     - d/p/drop-unsupported-systemd-condition-environment.patch
     - d/p/revert-551f560d-cloud-config-after-snap-seeding.patch
+    - d/p/netplan99-cannot-use-default.patch
+  * Upstream snapshot based on 24.3.1. (LP: #2079224).
+    List of changes from upstream can be found at
+    https://raw.githubusercontent.com/canonical/cloud-init/24.3.1/ChangeLog
 
- -- James Falcon <james.falcon@canonical.com>  Tue, 06 Aug 2024 09:04:37 -0500
+ -- Chad Smith <chad.smith@canonical.com>  Fri, 06 Sep 2024 12:18:16 -0600
 
 cloud-init (24.2-0ubuntu1~20.04.1) focal; urgency=medium