chore: Add Changelog and Release Notes for v0.42.8 (#9807)

* chore: Add Changelog and Release Notes for v0.42.8

* Change date

CHANGELOG.md

@@ -36,6 +36,8 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ## Unreleased
 
+## [v0.42.8](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.42.8) - 2021-07-30
+
 ### Features
 
 * [\#9750](https://github.com/cosmos/cosmos-sdk/pull/9750) Emit events for tx signature and sequence, so clients can now query txs by signature (`tx.signature='<base64_sig>'`) or by address and sequence combo (`tx.acc_seq='<addr>/<seq>'`).

RELEASE_NOTES.md

@@ -1,10 +1,9 @@
-# Cosmos SDK v0.42.7 "Stargate" Release Notes
+# Cosmos SDK v0.42.8 "Stargate" Release Notes
 
 This release includes various minor bugfixes and improvments, including:
 
-- a x/capability initialization fix, which fixes the consensus error when using statesync,
-- CLI improvements such as fixing the `{appd} keys parse` subcommand and a better user error when `--chain-id` is not passed in the `{appd} tx multisign` subcommand,
-- add a new `Trace()` method on BaseApp to return the `trace` value for logging error stack traces,
-- IBC fixes for the `Transfer` event and telemetry metrics.
+- emit events for tx signature and sequence, so clients can now query txs by signature (`tx.signature='<base64_sig>'`) or by address and sequence combo (`tx.acc_seq='<addr>/<seq>'`),
+- support other signing algorithms than `secp256k1` with `--ledger` in with the CLI `keys add` command,
+- add missing documentation for CLI flag `--output json/text` to all `tx` cli commands.
 
-See the [Cosmos SDK v0.42.7 milestone](https://github.com/cosmos/cosmos-sdk/milestone/48?closed=1) on our issue tracker for the exhaustive list of all changes.
+See the [Cosmos SDK v0.42.8 milestone](https://github.com/cosmos/cosmos-sdk/milestone/50?closed=1) on our issue tracker for the exhaustive list of all changes.