build: update to setup-node@v2

commit-lint.yml uses setup-node@v1 but all our other GitHub Actions use
v2. Update commit-lint.yml.

PR-URL: https://github.com/nodejs/node/pull/39366
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

.github/workflows/commit-lint.yml

@@ -11,7 +11,7 @@ jobs:
           # Last 100 commits should be enough for a PR
           fetch-depth: 100
       - name: Use Node.js 12
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v2
         with:
           node-version: 12.x
       - name: Validate commit messages