Upgrade to Node 14 for Actions (#2928)

Summary:
I believe that matches what we have internally. This has been causing some upgrades to fail.

Pull Request resolved: https://github.com/facebook/flipper/pull/2928

Reviewed By: aigoncharov

Differential Revision: D31324394

Pulled By: passy

fbshipit-source-id: eec38dcc6322e3e8957bbc20bf74d343855be8c0

.github/workflows/nodejs-pkg.yml

@@ -14,7 +14,7 @@ jobs:
     - uses: actions/checkout@v1
     - uses: actions/setup-node@v1
       with:
-        node-version: '12.x'
+        node-version: '14.x'
     - name: install
       working-directory: ${{env.pkg-directory}}
       run: yarn