ci/cd: add a license checker

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>

.github/workflows/license.yaml

@@ -0,0 +1,26 @@
+name: "Software License Check"
+on:
+  push:
+    paths:
+      - 'go.mod'
+    branches:
+      - main
+  pull_request:
+    paths:
+      - 'go.mod'
+    # The branches below must be a subset of the branches above
+    branches: [main]
+
+jobs:
+  license-check:
+    runs-on: ubuntu-latest
+    name: License Check
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          go-version: 1.17.x
+      - name: Install go-licenses
+        run: go install github.com/google/go-licenses@latest
+      - name: Check for forbidden licenses
+        run: make check-licenses