add gitea workflow

.gitea/workflows/docker-builder.yml

@@ -0,0 +1,41 @@
+name: Docker Build
+
+on:
+  push:
+    branches:
+      - 3.23
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: self-hosted
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set build metadata
+        run: |
+          echo "BUILD_DATE=$(date -u +%Y-%m-%dT%H:%M:%SZ)" >> $GITEA_ENV
+          echo "VERSION=${GITEA_REF_NAME}" >> $GITEA_ENV
+
+#      - name: Build Docker image
+#        run: |
+#          docker build \
+#            --build-arg BUILD_DATE=${BUILD_DATE} \
+#            --build-arg VERSION=${VERSION} \
+#            -t docker-baseimage-alpine:${VERSION} .
+      - name: Login to registry
+        run: |
+          echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login \
+            git.pi-farm.de \
+            -u ${{ secrets.REGISTRY_USER }} \
+            --password-stdin
+
+      - name: Build & push
+        run: |
+          docker build \
+            --build-arg BUILD_DATE=${BUILD_DATE} \
+            --build-arg VERSION=${VERSION} \
+            -t git.pi-farm.de/pi-farm/docker-baseimage-alpine:${VERSION} .
+          docker push git.pi-farm.de/pi-farm/docker-baseimage-alpine:${VERSION}