Added file license header checking to CI

.github/workflows/license-header.yml

@@ -0,0 +1,20 @@
+name: citra-license
+
+on:
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  license-header:
+    runs-on: ubuntu-latest
+    container:
+      image: opensauce04/lime3ds-build:latest
+      options: -u 1001
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Fetch master branch
+        run: git fetch origin master:master
+      - name: Check license headers
+        run: ./.ci/license-header.rb