add workflow to fetch spdx licenses

Author: elrayle

.github/workflows/fetch-licenses.yaml

@@ -0,0 +1,48 @@
+name: Fetch Licenses
+
+on:
+    workflow_dispatch: # Allows manual triggering of the workflow
+    schedule:
+        - cron: '0 0 * * *' # Runs at midnight ET
+    push:
+        branches:
+            - elr/update-licenses
+
+jobs:
+    fetch-licenses:
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout Repository
+              uses: actions/checkout@v2
+              with:
+                  ref: auto-update-licenses
+
+            - name: Checkout SPDX Repository
+              uses: actions/checkout@v2
+              with:
+                  repository: spdx/license-list-data
+                  path: spdx-license-list-data
+
+            - name: Copy Licenses
+              run: |
+                  cp spdx-license-list-data/json/licenses.json cmd/licenses.json
+                  cp spdx-license-list-data/json/exceptions.json cmd/exceptions.json
+
+            - name: Check for changes
+              run: |
+                  git diff --exit-code -- cmd/licenses.json cmd/exceptions.json || exit 0
+                
+            - name: Run license extraction
+              run: |
+                  cd cmd
+                  go run . extract -l -e
+                  cd ..
+
+            - name: Commit and push
+              run: |
+                  git config --local user.email "[email protected]"
+                  git config --local user.name "GitHub Action"
+                  git add cmd/
+                  git commit -m "Add updated license files - $(date)" -a
+                  git push