use current container image for build

Author: Sesu8642

.github/workflows/build.yml

@@ -12,7 +12,7 @@ jobs:
       runs-on: ubuntu-latest
       container:
         # trying to be close to the f-droid build to detect failures early
-        image: registry.gitlab.com/fdroid/fdroidserver:buildserver-bullseye
+        image: registry.gitlab.com/fdroid/fdroidserver:buildserver-bookworm
       env:
         ANDROID_HOME: /opt/android-sdk
       steps: