github/workflows: prepend config name to artifact

Prepend the name of the current configuration to the name
of the uploaded artifact, thereby enabling the upload
of all artifacts generated by the entire build matrix.

Neat.

.github/workflows/lone.yml

@@ -74,7 +74,7 @@ jobs:
     - name: Upload lone executable artifact
       uses: actions/upload-artifact@v4
       with:
-        name: lone
+        name: ${{ matrix.env.CONFIGURATION }}-lone
         path: build/${{ matrix.env.CONFIGURATION }}/lone
         compression-level: 9
         overwrite: false