use os for the artifact name

to avoid conflict between jobs

Author: vladak

.github/workflows/build.yml

@@ -59,5 +59,6 @@ jobs:
     - name: Upload artifact
       uses: actions/upload-artifact@v4
       with:
+        name: opengrok-${{ matrix.os }}.tar.gz
         path: distribution/target/opengrok-*.tar.gz
         compression-level: 0