setup-node needs a version spec (microsoft#48688)

Author: andrewbranch

.github/workflows/twoslash-repros.yaml

@@ -29,7 +29,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: actions/setup-node
+    - uses: actions/setup-node@v1
       with:
         node-version: 16
     - uses: microsoft/TypeScript-Twoslash-Repro-Action@master