Start release v0.21.0 (thanos-io#4285)

* Add missing entries to CHANGELOG

Signed-off-by: Prem Saraswat <prmsrswt@gmail.com>

* Cut CHANGELOG for v0.21.0

Signed-off-by: Prem Saraswat <prmsrswt@gmail.com>

CHANGELOG.md

@@ -13,8 +13,24 @@ We use _breaking :warning:_ to mark changes that are not backward compatible (re
 ## Unreleased
 
 ### Added
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+-
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+### Fixed
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+-
+
+### Changed
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+-
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+## [v0.21.0](https://github.com/thanos-io/thanos/releases/tag/v0.21.0) - 2021.05.28
+
+### Added
+
 - [#4117](https://github.com/thanos-io/thanos/pull/4117) Mixin:  new alert ThanosReceiveTrafficBelowThreshold to flag if the ingestion average of the last hour dips below 50% of the ingestion average for the last 12 hours.
 - [#4107](https://github.com/thanos-io/thanos/pull/4107) Store: `LabelNames` and `LabelValues` now support label matchers.
+- [#3940](https://github.com/thanos-io/thanos/pull/3940) Sidecar: Added matchers support to `LabelValues`
 - [#4171](https://github.com/thanos-io/thanos/pull/4171) Docker: Busybox image updated to latest (1.33.1)
 - [#4175](https://github.com/thanos-io/thanos/pull/4175) Added Tag Configuration Support Lightstep Tracing
 - [#4176](https://github.com/thanos-io/thanos/pull/4176) Query API: Adds optional `Stats param` to return stats for query APIs
@@ -24,13 +40,12 @@ We use _breaking :warning:_ to mark changes that are not backward compatible (re
 - [#3707](https://github.com/thanos-io/thanos/pull/3707) Tools: Added `--rewrite.to-relabel-config` to bucket rewrite tool to support series relabel from given blocks.
 
 ### Fixed
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+- [#4105](https://github.com/thanos-io/thanos/pull/4105) Tools: Add glob support for filepath in tools command
 ### Changed
 
 - [#4223](https://github.com/thanos-io/thanos/pull/4223) Query: federated exemplars API only add replica labels to series labels, not to exemplar labels.
 
-### Removed
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 ## [v0.20.2](https://github.com/thanos-io/thanos/releases/tag/v0.20.2) - 2021.05.20
 
 ### Fixed

VERSION

@@ -1 +1 @@
-0.21.0-dev
+0.22.0-dev