Add changelog

Author: nateprewitt

.changes/next-release/enhancement-cloudformation-37336.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "``cloudformation``",
+  "description": "High-level Cloudformation commands such as ``deploy`` and ``package`` will now fallback to SHA256 for checksumming if MD5 isn't present on the host"
+}