move to java 21

Author: jakubskopal

.github/workflows/release.yml

@@ -0,0 +1,33 @@
+name: Build and Release new docker images
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - master
+
+permissions:
+  contents: read
+  actions: read
+  checks: write
+  packages: write
+
+jobs:
+  build:
+    name: Build and Release Docker host
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Login to GHCR
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build and push Showcase Server
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          push: true
+          tags: ghcr.io/${{ github.repository_owner }}/bw-zuni-docker-host:latest
+

Dockerfile

@@ -1,4 +1,4 @@
-FROM openjdk:11-jdk-slim
+FROM eclipse-temurin:21
 RUN apt-get update && apt-get install -y \
     curl \
     tesseract-ocr \