CI(GitHub Actions): use .node-version

Summary:
Ref D497. Centralize management for node version management.

Signed-off-by: Yongmin Hong <revi@omglol.email>

Test Plan: land and wait for next npm-pub release.

Reviewers: O1 revi & automations, revi

Reviewed By: O1 revi & automations, revi

Tags: #npm

Differential Revision: https://issuetracker.revi.xyz/D502

.github/workflows/npm-pub.yml

@@ -22,7 +22,7 @@ jobs:
       - name: 'Setup node.js'
         uses: actions/setup-node@v4
         with:
-          node-version: '20.x'
+          node-version-file: '.node-version'
           cache: npm
           registry-url: 'https://registry.npmjs.org'
       - name: 'Install dependencies'
@@ -47,7 +47,7 @@ jobs:
       - name: 'Setup node.js'
         uses: actions/setup-node@v4
         with:
-          node-version: '20.x'
+          node-version-file: '.node-version'
           cache: npm
           registry-url: 'https://registry.npmjs.org'
       - name: 'Install dependencies'