[ci] Switching to nightly flatpak container

.gitea/workflows/build-flatpak.yml

@@ -10,37 +10,19 @@ on:
 jobs:
   flatpak:
     name: Build Flatpak
-    # Use a VM runner if possible. If using a docker runner, ensure it supports namespaces.
     runs-on: ubuntu-latest
+    container:
+      image: bilelmoussaoui/flatpak-github-actions:gnome-nightly
+      options: --privileged --device=/dev/fuse
 
     steps:
       - name: Checkout Code
         uses: actions/checkout@v4
 
-      - name: Install Flatpak Tools
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y flatpak flatpak-builder
-          # Initialize the user installation (safer for CI than system-wide)
-          flatpak --user remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
-
-      - name: Cache Flatpak Dependencies
-        uses: actions/cache@v4
-        with:
-          path: ~/.local/share/flatpak
-          key: flatpak-${{ runner.os }}-${{ hashFiles('build-aux/com.ranfdev.Notify.Devel.json') }}
-
-      - name: Install Runtimes
-        run: |
-          # Extract runtime from your manifest to install it
-          # This assumes your manifest defines org.freedesktop.Platform/x86_64/23.08
-          # You may need to hardcode this or parse your YAML
-          flatpak --user install -y flathub org.freedesktop.Platform//23.08 org.freedesktop.Sdk//23.08
-
       - name: Build Flatpak
         run: |
-          rm -rf .flatpak-builder build-dir repo
-          flatpak-builder --force-clean --user --install-deps-from=flathub --repo=repo build-dir build-aux/com.ranfdev.Notify.Devel.json
+          rm -rf .flatpak-builder build-dir repo _build
+          flatpak-builder --force-clean --user --install-deps-from=flathub --repo=repo build-dir build-aux/com.ranfdev.Notify.Devel.json 2>&1
 
       - name: Build Bundle
         run: |