Add back job strategy for workflow jobs

.github/workflows/spectesting.yml

@@ -21,28 +21,36 @@ jobs:
     runs-on: self-hosted
     name: Vagrant-Spec Start Hosts
     needs: setup-packet
+    strategy:
+      matrix:
+        host_os: ['hashicorp/bionic64']
+        guest_os: ['hashicorp-vagrant/ubuntu-16.04']
     steps:
       - name: Code Checkout
         uses: actions/checkout@v1
-      - name: Run Tests with host ${{ matrix.host_os }} using guest ${{ matrix.guest_os }}
+      - name: Create packet host for tests
         run: .ci/spec/create-hosts.sh
         working-directory: ${{github.workspace}}
         env:
-          VAGRANT_HOST_BOXES: hashicorp/bionic64
-          VAGRANT_GUEST_BOXES: hashicorp-vagrant/ubuntu-16.04
+          VAGRANT_HOST_BOXES: ${{matrix.host_os}}
+          VAGRANT_GUEST_BOXES: ${{matrix.guest_os}}
 
   spec-tests:
     if: github.repository == 'hashicorp/vagrant-blackbox'
     runs-on: self-hosted
     name: Vagrant-Spec Tests
     needs: setup-hosts
+    strategy:
+      matrix:
+        host_os: ['hashicorp/bionic64']
+        guest_os: ['hashicorp-vagrant/ubuntu-16.04']
     steps:
-      - name: Run Tests with all hosts and guests
+      - name: Run Tests with host ${{ matrix.host_os }} using guest ${{ matrix.guest_os }}
         run: .ci/spec/run-test.sh
         working-directory: ${{github.workspace}}
         env:
-          VAGRANT_HOST_BOXES: hashicorp/bionic64
-          VAGRANT_GUEST_BOXES: hashicorp-vagrant/ubuntu-16.04
+          VAGRANT_HOST_BOXES: ${{matrix.host_os}}
+          VAGRANT_GUEST_BOXES: ${{matrix.guest_os}}
 
   cleanup:
     if: github.repository == 'hashicorp/vagrant-blackbox'