Merge branch 'renovate/hydra-0.x' into 'main'

Update Helm release hydra to v0.21.8

See merge request !89

helmchart/single-sign-on/Chart.yaml

 apiVersion: v2
 description: A Helm chart for Stackspin's Single sign-on components
 name: single-sign-on
-version: 0.7.7
+version: 0.7.8
 icon: https://stackspin.net/assets/images/logo.svg
 dependencies:
   # https://k8s.ory.sh/helm/hydra.html
   - name: hydra
-    version: 0.21.5
+    version: 0.21.8
     repository: "https://k8s.ory.sh/helm/charts"
     tags:
       - single-sign-on