use expression syntax

Author: SirYwell

.github/workflows/build-pr.yml

@@ -22,7 +22,7 @@ jobs:
         run: ./gradlew build -s
       - name: Archive artifacts
         uses: actions/upload-artifact@v4
-        if: matrix.os == 'ubuntu-latest' # only upload once, use linux builds
+        if: ${{ matrix.os == 'ubuntu-latest' }} # only upload once, use linux builds
         with:
             name: FastAsyncWorldEdit-SNAPSHOT
             path: worldedit-bukkit/build/libs/FastAsyncWorldEdit-*.jar