chore(deps): update roundcubemail docker tag to v1.6.11

.drone.yml

@@ -26,7 +26,7 @@ steps:
 - name: markdown lint
   commands:
   - markdownlint *.md
-  image: git.cryptic.systems/volker.raschek/markdownlint:0.45.0
+  image: git.cryptic.systems/volker.raschek/markdownlint:0.44.0
   resources:
     limits:
       cpu: 150

Chart.yaml

@@ -3,7 +3,7 @@ name: roundcube
 description: Helm chart for roundcube
 type: application
 version: "0.2.1"
-appVersion: "1.5.3-apache"
+appVersion: "1.6.11-apache"
 icon: https://upload.wikimedia.org/wikipedia/commons/e/e3/Roundcube_logo_icon.svg
 
 keywords: