ci: throw QEMU back in

Author: william-silversmith

.github/workflows/build_aarch64.yml

@@ -19,6 +19,10 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
+      - name: Set up QEMU
+        if:  ${{ matrix.arch == 'aarch64' }}
+        uses: docker/setup-qemu-action@v2
+
       - name: Install OpenSSL
         if:  ${{ matrix.arch == 'aarch64' }}
         run: sudo apt-get update && sudo apt-get install -y libssl-dev