docs: add release notes

Author: darioAnongba

docs/release-notes/release-notes-0.7.0.md

@@ -168,6 +168,10 @@
   user to specify a custom amount to send to a V2 address that doesn't have an
   amount specified.
 
+- The `BurnAsset` RPC has a new field `asset` that allows the user to specify
+  the asset to burn by ID or GroupKey. The previous `asset` field is deprecated
+  and renamed as `asset_legacy`.
+
 ## tapcli Additions
 
 - [Rename](https://github.com/lightninglabs/taproot-assets/pull/1682) the mint
@@ -185,6 +189,9 @@
 - CLI JSON output [now](https://github.com/lightninglabs/taproot-assets/pull/1821)
   includes unset and zero-valued proto fields (e.g. transaction output indexes).
   This ensures consistent output shape across all proto messages.
+  
+- The `tapcli assets burn` command now has a new flag `--group_key` that
+  allows users to burn assets by group key.
 
 # Improvements