try to fix ganymede build

.gitea/workflows/build-nginx.yaml

@@ -9,14 +9,6 @@ jobs:
   "Build nginx docker images":
     runs-on: woryzen
     steps:
-      -
-        name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3.4.0
-        with:
-          driver: docker-container
-          platforms: |
-            linux/amd64
-            linux/arm64
       -
         name: Login to Gitea container registry
         uses: docker/login-action@v3
@@ -28,6 +20,7 @@ jobs:
         name: Build and push nginx vanilla images
         uses: docker/build-push-action@v6
         with:
+          builder: multiplatform-builder
           context: "{{defaultContext}}:nginx"
           platforms: |
             linux/amd64
@@ -50,6 +43,7 @@ jobs:
         name: Build and push nginx custom images
         uses: docker/build-push-action@v6
         with:
+          builder: multiplatform-builder
           context: "{{defaultContext}}:nginx"
           platforms: |
             linux/amd64

jupyter-ganymede/Dockerfile

@@ -4,7 +4,12 @@ RUN --mount=type=cache,target=/var/cache/apk/,sharing=locked \
     apk add python3 python3-dev pipx gcc g++ musl-dev linux-headers which curl libffi-dev git
 RUN adduser jovyan -u 1000 --system -s /bin/sh -h /home/jovyan
 
-FROM --platform=$BUILDPLATFORM build-base AS java-build
+FROM --platform=$BUILDPLATFORM alpine:3.22 AS java-build
+RUN --mount=type=cache,target=/var/cache/apk/,sharing=locked \
+    apk update &&\
+    apk add python3 python3-dev pipx gcc g++ musl-dev linux-headers which curl libffi-dev git
+RUN adduser jovyan -u 1000 --system -s /bin/sh -h /home/jovyan
+
 RUN --mount=type=cache,target=/var/cache/apk/,sharing=locked \
     apk add openjdk11-jdk maven
 USER jovyan