fix: remove legacy REST endpoints for broadcast & encode (v0.44.x) (c…

…osmos#10041)

* fix: remove legacy REST endpoints for broadcast & encode

* add changelog

* update changelog

* fix amino tx marshaling test

* try to fix x/auth/client/rest tests

* changing tx broadcast request type

* remove auth client/rest_test.go

Co-authored-by: Robert Zaremba <robert@zaremba.ch>

CHANGELOG.md

@@ -56,7 +56,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### API Breaking Changes
 * (client/tx) [\#9421](https://github.com/cosmos/cosmos-sdk/pull/9421/) `BuildUnsignedTx`, `BuildSimTx`, `PrintUnsignedStdTx` functions are moved to
   the Tx Factory as methods.
-
+
+### Client Breaking Changes
+* [\#10041](https://github.com/cosmos/cosmos-sdk/pull/10041) Remove broadcast & encode legacy REST endpoints. Please see the [REST Endpoints Migration guide](https://docs.cosmos.network/master/migrations/rest.html) to migrate to the new REST endpoints.
+
 ## [v0.43.0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.43.0) - 2021-08-10
 
 ### Features