Bootstrap CI for Vagrant setup tutorial

Signed-off-by: Gianluca Arbezzano <gianarb92@gmail.com>

.github/workflows/vagrant-packet.yaml

@@ -0,0 +1,17 @@
+name: Setup with Vagrant on Packet
+on:
+  push:
+  pull_request:
+    types: [labeled]
+
+jobs:
+  vagrant-setup:
+    if: contains(github.event.pull_request.labels.*.name, 'ci-check/vagrant-setup')
+    runs-on: vagrant
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Vagrant Test
+      run: |
+        export VAGRANT_DEFAULT_PROVIDER="virtualbox"
+        go test --timeout 1h -v ./test/_vagrant