🔖(minor) release 3.1.0

Added:
- 🚩(backend) add feature flag for the footer
- 🔧(backend) add view to manage footer json
- ✨(frontend) add custom css style
- 🚩(frontend) conditionally render AI button only
  when feature is enabled

Changed:
- 🚨(frontend) block button when creating doc

Fixed:
- 🐛(back) validate document content in serializer
- 🐛(frontend) fix selection click
  past end of content

src/helm/helmfile.yaml

@@ -1,7 +1,7 @@
 environments:
   dev:
     values:
-      - version: 3.0.0
+      - version: 3.1.0
 ---
 repositories:
 - name: bitnami

src/helm/impress/Chart.yaml

@@ -1,5 +1,5 @@
 apiVersion: v2
 type: application
 name: docs
-version: 3.0.0
+version: 3.1.0
 appVersion: latest