add a GitHub Action to automatically update the license every year (#14)

.github/workflows/update-license.yml

@@ -0,0 +1,24 @@
+---
+name: Update copyright years
+
+on:
+  schedule:
+    - cron: '0 4 1 1 *'  # Midnight of December 31st (GitHub Action are using UTC)
+  workflow_dispatch:
+
+jobs:
+  update-license-year:
+    runs-on: ubuntu-latest
+    steps:
+
+      - uses: actions/[email protected]
+
+      - uses: FantasticFiasco/[email protected]
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          commitAuthorName: 'kube1st'
+          commitAuthorEmail: ${{ secrets.GPG_EMAIL }}
+          gpgPrivateKey: ${{ secrets.GPG_KEY }}
+          gpgPassphrase: ${{ secrets.GPG_PASSPHRASE }}
+          commitTitle: "chore: update license years with {{currentYear}}"
+          prTitle: "chore: update license years with {{currentYear}}"