Merge pull request #9473 from gyuho/deprecate-policy

*: document deprecate policy in CHANGELOG-4.0

CHANGELOG-3.4.md

@@ -22,9 +22,9 @@ See [code changes](https://github.com/coreos/etcd/compare/v3.3.0...v3.4.0) and [
 
 ### Breaking Changes
 
-- **Deprecated `etcd --ca-file` flag**, instead [use `--trusted-ca-file`](https://github.com/coreos/etcd/pull/9470) (`--ca-file` has been deprecated since v2.1).
-- **Deprecated `etcd --peer-ca-file` flag**, instead [use `--peer-trusted-ca-file`](https://github.com/coreos/etcd/pull/9470) (`--peer-ca-file` has been deprecated since v2.1).
-- **Deprecated `pkg/transport.TLSInfo.CAFile` field**, instead [use `pkg/transport.TLSInfo.TrustedCAFile`](https://github.com/coreos/etcd/pull/9470) (`CAFile` has been deprecated since v2.1).
+- **Remove `etcd --ca-file` flag**, instead [use `--trusted-ca-file`](https://github.com/coreos/etcd/pull/9470) (`--ca-file` has been deprecated since v2.1).
+- **Remove `etcd --peer-ca-file` flag**, instead [use `--peer-trusted-ca-file`](https://github.com/coreos/etcd/pull/9470) (`--peer-ca-file` has been deprecated since v2.1).
+- **Remove `pkg/transport.TLSInfo.CAFile` field**, instead [use `pkg/transport.TLSInfo.TrustedCAFile`](https://github.com/coreos/etcd/pull/9470) (`CAFile` has been deprecated since v2.1).
 - Drop [ACIs from official release](https://github.com/coreos/etcd/pull/9059).
   - [AppC was officially suspended](https://github.com/appc/spec#-disclaimer-), as of late 2016.
   - [`acbuild`](https://github.com/containers/build#this-project-is-currently-unmaintained) is not maintained anymore.

CHANGELOG-4.0.md

@@ -0,0 +1,14 @@
+
+
+## v4.0.0 (TBD)
+
+See [code changes](https://github.com/coreos/etcd/compare/v3.3.0...v4.0.0) and [v4.0 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_4_0.md) for any breaking changes.
+
+### Breaking Changes
+
+- Deprecate [v2 storage backend](https://github.com/coreos/etcd/issues/9232).
+  - v2 API is still supported via [v2 emulation]().
+- `clientv3.Client.KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAliveResponse, error)` is now [`clientv4.Client.KeepAlive(ctx context.Context, id LeaseID) <-chan *LeaseKeepAliveResponse`](TODO).
+  - Similar to `Watch`, [`KeepAlive` does not return errors](https://github.com/coreos/etcd/issues/7488).
+  - If there's an unknown server error, kill all open channels and create a new stream on the next `KeepAlive` call.
+