docs: changelog entry for new sparkplug decode and encode functions

changes/ee/feat-11169.md

@@ -0,0 +1,26 @@
+Two new built-in functions `sparkplug_decode` and `sparkplug_encode` have been added to the rule engine SQL like language. These functions are used to decode and encode Sparkplug B messages. The functions are used as follows:
+
+Decode a Sparkplug B message:
+
+```sql
+select
+  sparkplug_decode(payload) as decoded
+from t
+
+```
+
+Encode a Sparkplug B message:
+
+```sql
+select
+  sparkplug_encode(json_decode(payload)) as encoded
+from t
+```
+
+One can also specify a Sparkplug B message type by specifying it as the second argument to the `sparkplug_decode` and `sparkplug_encode` functions. The default is `Payload`:
+
+```sql
+select
+  sparkplug_encode(sparkplug_decode(payload, 'Payload'), 'Payload') as encoded
+from t
+```