Setup FOSSA (#3836)

.github/workflows/fossascan.yaml

@@ -0,0 +1,26 @@
+name: FOSSA License Scan
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  fossa-scan:
+    runs-on: ubuntu-latest
+    env:
+      GRADLE_OPTS: -Dorg.gradle.daemon=false
+    steps:
+      - name: Checkout Repo
+        uses: actions/checkout@v2
+
+      - name: Setup Java
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+
+      - name: Run FOSSA Scan
+        uses: fossas/fossa-action@v1
+        if: ${{ github.repository == 'detekt/detekt'}}
+        with:
+          api-key: ${{ secrets.FOSSA_API_KEY }}