voltha-infra: disable non function pdb deployment

* after updating the kubernetes cluster version for the berlin-lab, we
  need to also align the API versions used when creating kubernetes
  resources
* within the voltha-infra chart, the onos-classic chart is listed as a
  dependency, which has the atomix chart as a dependency
* within the atomix helm chart, a PodDisruptionBudget is deployed, using
  the apiVersion policy/v1beta1
  https://github.com/atomix/atomix-helm-charts/blob/master/atomix/templates/pdb.yaml#L6
* this apiVersion has been removed from Kubernetes (and been replaced
  with policy/v1), but the atomix helm Chart was last patched 2 years
  ago, leading to the assumption that it is unmaintained
* given that the other settings for atomix in the values.yml (e.g.
  replicas: 0) of voltha-infra suggest that atomix is not used, but was
  just added as a unwanted dependency of onos-classic, it might be
  easiest here to also just disable the deployment of the
  PodDisruptionBudget
* update VERSION tag
* update the voltha chart version to please the linter
* update voltha-infra chart version to 2.12.7

Signed-off-by: Jan Klare <jan.klare@bisdn.de>
Change-Id: Ie82239d3bc744f8064a4cd5e0d3a090ccd715c05
Signed-off-by: Cristina de Francisco <cristina.defrancisco@bisdn.de>
diff --git a/voltha/Chart.yaml b/voltha/Chart.yaml
index 3b6785d..011448b 100644
--- a/voltha/Chart.yaml
+++ b/voltha/Chart.yaml
@@ -17,7 +17,7 @@
 
 ## Chart version for package: 'voltha'
 ##   Increment when Chart.yaml changes
-version: "2.12.17"
+version: "2.12.18"
 
 description: "A Helm chart for Voltha based on K8S resources in Voltha project"
 keywords: