ci: Add scancode github action

Use the zephyr project's `scancode` github action to scan our code for
license header violations.

Author: rwalton-arm

.github/license_config.yml

@@ -0,0 +1,17 @@
+license:
+  main: apache-2.0
+  category: Permissive
+exclude:
+  extensions:
+    - yml
+    - yaml
+    - html
+    - rst
+    - conf
+    - cfg
+    - ini
+    - toml
+    - in
+    - txt
+  langs:
+    - HTML

.github/workflows/scancode.yml

@@ -0,0 +1,24 @@
+name: Scancode
+
+on: [pull_request]
+
+jobs:
+  scancode_job:
+    runs-on: ubuntu-latest
+    name: Scan code for licenses
+    steps:
+    - uses: actions/checkout@v1
+    - name: Scan the code
+      id: scancode
+      uses: zephyrproject-rtos/action_scancode@v1
+      with:
+        directory-to-scan: 'scan/'
+    - name: Artifact Upload
+      uses: actions/upload-artifact@v1
+      with:
+        name: scancode
+        path: ./artifacts
+
+    - name: Verify
+      run: |
+        test ! -s ./artifacts/report.txt || (cat ./artifacts/report.txt && exit 1 )

news/202201101535.misc

@@ -0,0 +1 @@
+Remove `licenseheaders` tool and replace it with `scancode`.