add workflows

.github/workflows/vunit_tests.yml

@@ -0,0 +1,18 @@
+name: VUnit Tests
+
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: '0 0 * * 5'
+  workflow_dispatch:
+
+jobs:
+
+  Test:
+    runs-on: ubuntu-latest
+    steps:
+
+    - uses: actions/checkout@v2
+
+    - uses: VUnit/vunit_action@master