Merge #1241

1241: Change extensions/v1beta to apps/v1 to be compliant with Kubernetes 1.16 r=mergify[bot] a=WebSpider


## What type of PR?

Enhancement

## What does this PR do?

Changes to Kubernetes YAML files to be able to use this in Kubernetes 1.16

### Related issue(s)
- Fixes #1237

## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- N/A In case of feature or enhancement: documentation updated accordingly
- [X] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/guide.html#changelog) entry file.


Co-authored-by: WebSpider <webspider@bitlair.nl>
Co-authored-by: micw <michael@wyraz.de>

docs/kubernetes/mailu/admin.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: mailu-admin

docs/kubernetes/mailu/fetchmail.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: mailu-fetchmail

docs/kubernetes/mailu/imap.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: mailu-imap

docs/kubernetes/mailu/ingress.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Ingress
 metadata:
   name: mailu-ingress

docs/kubernetes/mailu/redis.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: mailu-redis

docs/kubernetes/mailu/security.yaml

@@ -1,5 +1,4 @@
-
+apiVersion: apps/v1
-apiVersion: extensions/v1beta1
 kind: Deployment
 metadata:
   name: mailu-security

docs/kubernetes/mailu/smtp.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: mailu-smtp

docs/kubernetes/mailu/webdav.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: mailu-webdav

docs/kubernetes/mailu/webmail.yaml

@@ -1,5 +1,4 @@
-
+apiVersion: apps/v1
-apiVersion: extensions/v1beta1
 kind: Deployment
 metadata:
   name: mailu-roundcube

docs/kubernetes/nginx/default-http-backend.yaml

@@ -1,4 +1,4 @@
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1
 kind: Deployment
 metadata:
   name: default-http-backend

towncrier/newsfragments/1241.fix

@@ -0,0 +1 @@
+Kubernetes manifests updated to be compatible with Kubernetes 1.16 (breaks compatibility with older k8s versions)