Update the changelog to reflect recent PRs (#1605)

Making my life as a release shepherd easy.

Signed-off-by: Goutham Veeramachaneni <gouthamve@gmail.com>

Author: gouthamve

CHANGELOG.md

@@ -1,11 +1,15 @@
 ## master / unreleased
 
-* [FEATURE] You can now specify `http_config` on alert receivers #929
 * [CHANGE] Flags changed due to changes upstream in Prometheus Alertmanager #929:
   * `alertmanager.mesh.listen-address` is now `cluster.listen-address`
   * `alertmanager.mesh.peer.host` and `alertmanager.mesh.peer.service` can be replaced by `cluster.peer`
   * `alertmanager.mesh.hardware-address`, `alertmanager.mesh.nickname`, `alertmanager.mesh.password`, and `alertmanager.mesh.peer.refresh-interval` all disappear.
-* [CHANGE] Retention period should now be a multiple of periodic table duration #1564
+* [CHANGE] Retention period must now be a multiple of periodic table duration #1564
+* [CHANGE] The value for the name label for the chunks memcache in all `cortex_cache_` metrics is now `chunksmemcache` (before it was `memcache`) #1569
+* [FEATURE] Makes the ingester flush each timeseries at a specific point in the max-chunk-age cycle with `-ingester.spread-flushes`. This means multiple replicas of a chunk are very likely to contain the same contents which cuts chunk storage space by up to 66%. #1578
+* [FEATURE] Honor HTTPS for custom S3 URLs #1603
+* [FEATURE] You can now point the query-frontend at a normal Prometheus for parallelisation and caching #1441
+* [FEATURE] You can now specify `http_config` on alert receivers #929
 * [FEATURE] Add option to use jump hashing to load balance requests to memcached #1554
 * [FEATURE] Add status page for HA tracker to distributors #1546