Build ffmpeg variants

.github/workflows/build.yml

@@ -75,3 +75,13 @@ jobs:
       matrix:
         target: [win64]
         variant: [gpl,lgpl]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Build ffmpeg
+        run: ./build.sh ${{ matrix.target }} ${{ matrix.variant }}
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: ffmpeg
+          path: artifacts/*