Merge pull request linode#408 from sibucan/lke-changelog-1.21.0

Add changelog update for LKE v1.21.0

Author: bbiggerr

src/content/changelog/lke-1-21-0.md

@@ -0,0 +1,28 @@
+---
+title: Linode Kubernetes Engine v1.21.0
+date: 2021-06-16T05:00:00.000Z
+version: 1.21.0
+changelog:
+  - Linode Kubernetes Engine
+---
+
+### Added
+
+* Added support for Graceful Node Shutdown in v1.20 and v1.21 clusters.
+  Existing clusters must recycle their nodes to finish the upgrade.
+* Added support for optional eBPF dataplanes by having new LKE nodes mount the
+  BPF filesystem on startup.
+
+### Changed
+
+* Upgraded coreDNS image from v1.8.0 to v1.8.4
+* Upgraded Calico CNI from v3.10.4 to v3.19.0
+* Upgraded cluster control plane components to latest available patch version:
+  v1.18.19, v1.19.11, and v1.20.7.
+
+### Fixed
+
+* Disabled rpcbind by default on new LKE nodes, to avoid having unnecessary
+  ports open.
+* Fixed bug where kubelet and kubeadm configs in v1.21 clusters would still
+  mention v1.20 text.