Prerelease fix

Author: negative0

.github/workflows/prerelease.yml

@@ -9,7 +9,7 @@ jobs:
       matrix:
         platform: [ubuntu-latest, macos-latest, windows-latest]
         node-version: [8.x, 10.x, 12.x]
-
+    runs-on: ${{ matrix.platform }}
     steps:
       - uses: actions/checkout@v1
       - name: Use Node.js ${{ matrix.node-version }}