Update root changelog for SECIO deprecation.
# Version 0.25.0 [2020-09-09]
+- Remove the deprecated `libp2p-secio` dependency. To continue to use
+ SECIO, add an explicit dependency on `libp2p-secio`. However,
+ transitioning to `libp2p-noise` is strongly recommended.
+
- Update `libp2p-yamux` to `0.22.0`. *This version starts a multi-release
upgrade process.* See the `libp2p-yamux` CHANGELOG for details.
