Update tests.yml

.github/workflows/tests.yml

@@ -214,13 +214,13 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Install QEMU
+      env:
+        QEMU_SRC: "http://archive.ubuntu.com/ubuntu/pool/universe/q/qemu"
+        QEMU_VER: "qemu-user-static_4\.2-.*_amd64.deb$"
       run: |
-        QEMU_URL=`curl -s http://archive.ubuntu.com/ubuntu/pool/universe/q/qemu/ \
-            | grep -o -E 'href="([^"#]+)"' \
-            | cut -d'"' -f2 \
-            | grep "qemu-user-static_4\.2-.*_amd64.deb$"`
-        wget $QEMU_URL -O qemu-user-static.deb
-        sudo dpkg -i qemu-user-static.deb
+        DEB=`curl -s $QEMU_SRC | grep -o -E 'href="([^"#]+)"' | cut -d'"' -f2 | grep $QEMU_VER`
+        wget $QEMU_SRC/$DEB
+        sudo dpkg -i $DEB
     - name: Install ${{ matrix.config.toolchain }}
       run: |
         sudo apt update