add release notes
concourse/concourse#4561
* All API payloads are now gzipped. This should help save bandwidth and make the web UI load faster. #4470
-#### <sub><sup><a name="4448" href="#4448">:link:</a></sup></sub> feature
+#### <sub><sup><a name="4448-4588" href="#4448-4588">:link:</a></sup></sub> feature
-* You can now use fly to pin a resource without unpinning it first. #4448
+* You can now pin a resource to different version without unpinning it first #4448, #4588.
#### <sub><sup><a name="4507" href="#4507">:link:</a></sup></sub> fix
