Add notice for buf-action (#38)

README.md

@@ -1,5 +1,10 @@
 # `buf-push-action`
 
+> [!NOTE]
+> This action has been deprecated in favor of the [`buf-action`][buf-action] which combines the
+> functionality of `buf-push-action` with the ability to run Buf commands in the same step. Please
+> see the [`buf-action`][buf-action] documentation for more information.
+
 This Action enables you to push [Buf modules][modules] to the [Buf Schema Registry][bsr] (BSR)
 Pushed modules are created with the Git commit SHA as the module tag.
 
@@ -161,6 +166,7 @@ jobs:
           buf_token: ${{ secrets.BUF_TOKEN }}
 ```
 
+[buf-action]: https://github.com/bufbuild/buf-action
 [breaking]: https://docs.buf.build/breaking
 [bsr]: https://docs.buf.build/bsr
 [bsr-token]: https://docs.buf.build/bsr/authentication