Bump to 1.21.0 (#566)

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/566
Reviewed-by: justusbunsi <justusbunsi@noreply.gitea.com>
Co-authored-by: pat-s <patrick.schratz@gmail.com>
Co-committed-by: pat-s <patrick.schratz@gmail.com>

Chart.yaml

@@ -3,7 +3,7 @@ name: gitea
 description: Gitea Helm chart for Kubernetes
 type: application
 version: 0.0.0
-appVersion: 1.20.5
+appVersion: 1.21.0
 icon: https://gitea.com/assets/img/logo.svg
 
 keywords:

README.md

@@ -706,7 +706,7 @@ extraVolumes:
 extraVolumeMounts:
   - name: gitea-themes
     readOnly: true
-    mountPath: "/data/gitea/public/css"
+    mountPath: "/data/gitea/public/assets/css"
 ```
 
 The secret can be created via `terraform`:
@@ -1051,6 +1051,15 @@ If you miss this, blindly upgrading may delete your Postgres instance and you ma
 
 <details>
 
+<summary>To 9.6.0</summary>
+
+Chart 9.6.0 ships with Gitea 1.21.0.
+While there are no breaking changes in the chart, please check the changes of the [1.21 release blog post](https://blog.gitea.com/release-of-1.21.0/).
+
+</details>
+
+<details>
+
 <summary>To 9.0.0</summary>
 
 This chart release comes with many breaking changes while aiming for a HA-ready setup.