extract bundle from local flatpak repo and try to install it

.github/workflows/lammps-gui-flatpak.yml

@@ -16,7 +16,7 @@ concurrency:
 jobs:
   build:
     name: Linux flatpak build
-    if: ${{ github.repository == 'lammps/lammps' }}
+    if: ${{ github.repository == 'akohlmey/lammps' }}
     runs-on: ubuntu-latest
 
     steps:
@@ -48,3 +48,7 @@ jobs:
                                --install-deps-from=flathub --state-dir=flatpak-state \
                                --user --ccache --default-branch=${{ github.ref_name }} \
                                flatpak-build tools/lammps-gui/org.lammps.lammps-gui.yml
+        flatpak build-bundle --runtime-repo=https://flathub.org/repo/flathub.flatpakrepo \
+                               --verbose  flatpak-repo LAMMPS-Linux-x86_64-GUI.flatpak \
+                               org.lammps.lammps-gui ${{ github.ref_name }}
+        flatpak install -y -v --user LAMMPS-Linux-x86_64-GUI.flatpak