Add docker buildx action

Signed-off-by: Pierre-Emmanuel Jacquier <15922119+pierre-emmanuelJ@users.noreply.github.com>

.github/workflows/cd.yml

@@ -15,6 +15,10 @@ jobs:
       -
         name: Unshallow
         run: git fetch --prune --unshallow
+      -
+        name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v1
       -
         name: Github Docker login
         run: echo ${{ secrets.GH_TOKEN }} | docker login docker.pkg.github.com -u ${{ github.actor }} --password-stdin