workflows: add LICENSE and README.md in archives

Author: af-airbus

.github/workflows/build.yml

@@ -114,6 +114,8 @@ jobs:
     runs-on: ubuntu-latest
     needs: [ build-linux-windows, build-frontend-macos-arm64, build-frontend-macos-x86_64]
     steps:
+      - uses: actions/checkout@v4
+
       - uses: actions/download-artifact@v4
         with:
           merge-multiple: true
@@ -123,8 +125,10 @@ jobs:
         run: |
           mkdir -p debug/soxy-debug-${{ env.SUFFIX }}
           mv artifacts/debug/* debug/soxy-debug-${{ env.SUFFIX }}/
+          cp LICENSE README.md debug/soxy-debug-${{ env.SUFFIX }}/
           mkdir -p release/soxy-release-${{ env.SUFFIX }}
           mv artifacts/release/* release/soxy-release-${{ env.SUFFIX }}/
+          cp LICENSE README.md release/soxy-release-${{ env.SUFFIX }}/
 
       - name: Upload debug artifacts
         uses: actions/upload-artifact@v4