feat/ci: upload Containerfile after building vib recipe

Signed-off-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

.github/workflows/vib-build.yml

@@ -104,6 +104,11 @@ jobs:
         recipe: 'recipe.yml'
         plugins: 'Vanilla-OS/vib-fsguard:v1.4'
     
+    - uses: actions/upload-artifact@v4
+      with:
+        name: Containerfile
+        path: Containerfile
+
     - name: Generate image name
       run: |
         REPO_OWNER_LOWERCASE="$(echo ${{ github.repository_owner }} | tr '[:upper:]' '[:lower:]')"