fix: use diddlesnaps/snapcraft-multiarch-action to generate arm64 snap (#949)

.github/workflows/linux.yml

@@ -101,7 +101,12 @@ jobs:
 
   snap:
     needs: release
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform:
+        - amd64
+        - arm64
 
     steps:
       - uses: actions/checkout@v2
@@ -109,18 +114,19 @@ jobs:
       - name: Check version
         run: ./stores/snapcraft/check_version.sh
 
-      - name: Install Snapcraft with LXD
-        uses: samuelmeuli/action-snapcraft@v1
+      - uses: docker/setup-qemu-action@v1
+        if: env.SHOULD_DEPLOY == 'yes'
+
+      - uses: diddlesnaps/snapcraft-multiarch-action@v1
         with:
-          use_lxd: true
+          path: stores/snapcraft
+          architecture: ${{ matrix.platform }}
+        id: build
         if: env.SHOULD_DEPLOY == 'yes'
 
-      - name: Build snap
-        run: ./stores/snapcraft/build.sh
-        if: env.SHOULD_DEPLOY == 'yes'
-
-      - name: Release snap
-        run: ./stores/snapcraft/release.sh
-        env:
-          SNAP_STORE_LOGIN: ${{ secrets.SNAP_STORE_LOGIN }}
+      - uses: snapcore/action-publish@v1
+        with:
+          store_login: ${{ secrets.SNAP_STORE_LOGIN }}
+          snap: ${{ steps.build.outputs.snap }}
+          release: stable
         if: env.SHOULD_DEPLOY == 'yes'