doc: add v0.2.1 changelog (#80)

CHANGELOG.md

@@ -1,5 +1,33 @@
 # Changelog
 
+## v0.2.1
+
+This is a minor release and upgrading is optional.
+
+### User Facing Changes
+
+- Adds a `--rpc.admin-state` CLI option to specify a file to persist config changes made via the RPC Admin APIs to.
+- Add `admin_sequencerActive` RPC method. Returns true if the node is actively sequencing, otherwise false.
+
+These features are merged from upstream code. Check the following PRs for more details:
+- https://github.com/ethereum-optimism/optimism/pull/6190
+- https://github.com/ethereum-optimism/optimism/pull/6105
+
+### Partial Changelog
+
+- #78: feat: support persist active api
+
+### Docker Images
+
+- ghcr.io/bnb-chain/op-node:v0.2.1
+- ghcr.io/bnb-chain/op-batcher:v0.2.1
+- ghcr.io/bnb-chain/op-proposer:v0.2.1
+
+### Full Changelog
+
+https://github.com/bnb-chain/opbnb/compare/v0.2.0...v0.2.1
+
+
 ## v0.2.0
 
 This is a hardfork release for the opBNB Testnet called Fermat.