CHANGELOG: Deprecate customVersion = v1beta1

We follow the release schedule of Kubernetes, according to which
deprecated versions are dropped after 3 releases.

`apps/v1beta2` was [introduced][v1beta2] in 1.8, thereby deprecating `v1beta1`, which
should therefore be dropped by 1.11.

`customVersion = v1beta1` maps to a controller that uses `apps/v1beta1`,
which won't be updated, and that must therefore be droppped.

[v1beta2]: https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.8.md#workloads-api-appsv1beta2

Signed-off-by: Lorenzo Manacorda <lorenzo@kinvolk.io>

CHANGELOG.md

@@ -17,6 +17,13 @@
 
 Please compare the `v1beta1` and `v1beta2` manifests of the standalone example in `examples/v1beta1/habitat.yml` and `examples/standalone/habitat.yml`, respectively, to compare the immediate differences between them. Please refer to `examples/persisted/habitat.yml` for an example of the persistence functionality.
 
+### Deprecations
+
+* `Habitat` Manifests that do not specify a `customVersion`, or that specify a
+`customVersion = v1beta1` are deprecated, and support for them will be removed
+when Kubernetes 1.11 is released. Please upgrade your manifests to the latest
+`customVersion`.
+
 ## [v0.5.1](https://github.com/kinvolk/habitat-operator/tree/v0.5.1) (14-2-2018)
 [Full changelog](https://github.com/kinvolk/habitat-operator/compare/v0.5.0...v0.5.1)