refactor: Add license information to files (#3093)

.github/workflows/reuse.yml

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: 2020 Free Software Foundation Europe e.V.
+# SPDX-License-Identifier: CC0-1.0
+name: 📋 REUSE Compliance Check
+
+permissions:
+  contents: read
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: REUSE Compliance Check
+        uses: fsfe/reuse-action@v4