Add qemu for arm builds on flatpak

.github/workflows/build_all.yml

@@ -63,6 +63,7 @@ jobs:
   flatpak:
     name: "Flatpak"
     runs-on: ubuntu-latest
+    timeout-minutes: 360
     env:
       date:
       ver:
@@ -75,6 +76,10 @@ jobs:
         - /usr/share/dotnet:/usr/share/dotnet
         - /opt/ghc:/opt/ghc1
         - /usr/local/share/boost:/usr/local/share/boost1
+    strategy:
+      matrix:
+        arch: [x86_64, aarch64]
+      fail-fast: false
     steps:
     - name: "Remove unneeded stuff to free disk space"
       run:
@@ -92,11 +97,22 @@ jobs:
         echo "ver_pure=$ver_pure" >> $GITHUB_ENV
         echo "date=$(date +'%Y%m%d')" >> $GITHUB_ENV
       shell: bash
+    - name: Install deps
+      if: ${{ matrix.arch != 'x86_64' }}
+      run: |
+        dnf -y install docker
+    - name: Set up QEMU
+      if: ${{ matrix.arch != 'x86_64' }}
+      id: qemu
+      uses: docker/setup-qemu-action@v2
+      with:
+        platforms: arm64
     - uses: flatpak/flatpak-github-actions/flatpak-builder@v6
       with:
         bundle: OrcaSlicer-Linux-flatpak_${{ env.ver }}.flatpak
         manifest-path: flatpak/io.github.softfever.OrcaSlicer.yml
         cache: true
+        arch: ${{ matrix.arch }}
     - name: Deploy Flatpak to nightly release
       if: ${{github.ref == 'refs/heads/main'}}
       uses: WebFreak001/deploy-nightly@v3.1.0